PR-486
Faculty, Staff, and Student Cooperators
Horticulture Technical/Professial Staff Farm Staff Students |
Agricultural Economics Professional Staff Agricultural Engineering Agronomy Entomology Technical Staff Students |
Plant Pathology Technical Staff Students UK Arboretum Grounds Manager |
This is a progress report and may not reflect exactly the final outcome of ongoing projects. Therefore, please do not reproduce project reports for distribution without permission of the authors.
Mention or display of a trademark, proprietary product, or firm in text or figures does not constitute an endorsement and does not imply approval to the exclusion of other suitable products or firms.
Dewayne Ingram, Chair, Department of Horticulture
The UK Nursery and Landscape Program coordinates the efforts of faculty, staff, and students in several departments in the College of Agriculture for the benefit of the Kentucky nursery and landscape industry. Our 2003 report has been organized according to our primary areas of emphasis: production and economics, pest management, and plant evaluation. These areas reflect stated industry needs, expertise available at UK, and the nature of research projects around the world generating information applicable to Kentucky. If you have questions or suggestions about a particular research project, please do not hesitate to contact us.
Although the purpose of this publication is to report research results, we have also highlighted below some of our Extension programs and undergraduate and graduate degree programs that are addressing the needs of the nursery/landscape industries.
We gratefully acknowledge the support of the Kentucky Horticulture Council's (KHC) grant that was made possible through Master Tobacco Settlement Funds and the Agricultural Development Board. These funds, along with U.S. Department of Agriculture funds through the New Crop Opportunities Center, have allowed us to expand our field research program and our Extension program to meet expanding industry needs and opportunities. The Agricultural Development Board has recently funded a second KHC grant to continue to expand our research and extension efforts in nursery crops and landscape horticulture. We will be able to continue support for the Nursery Crops Extension Associate in the western portion of the state for two more years and to hire two Extension Associates to work with nursery and greenhouse crop producers/marketers in Central Kentucky. We will also be able to expand our field research work at the Horticulture Research Farm in Lexington.
Specific, in-depth educational opportunities for garden centers, landscape contractors, nurseries, and arborists are being provided through two unique programs, the Best Management Workshops and the Integrated Pest Management Workshops.
The Best Management Practices (BMP) Workshop, a partnership between UK Cooperative Extension, KNLA, and WKNLA, is held in multiple locations and involves Extension agents, associates, specialists, and expertise from other states. The BMP program focused on weed control in 2003, utilizing the expertise of Drs. Robert McNiel and Mark Williams from UK and Dr. Larry Kuhns from Penn State. Out-of-state speakers were made possible by a grant from the UK College of Agriculture's Barnhart Fund for Excellence. The 5th Annual Best Management Practices will feature Dr. Dan Potter, UK Entomology, Dr. Dave Shetlar, Ohio State University, Kentucky Nursery Inspectors, and other UK specialists. The workshop will be offered in Louisville on February 17 and in Princeton, Kentucky, on February 18. In addition to practical information, the BMP workshop is a great way to earn pesticide and certified arborist CEUs.
The 2004 Integrated Pest Management (IPM) for Nursery Production Workshop Series will be held in June in Central Kentucky and in July in Western Kentucky. Thanks to Kentucky IPM funds, the program will feature four experts from Kentucky and beyond. IPM provides techniques that base spray decisions on pest population levels rather than guesswork. This on-location program specializes in hands-on application of IPM techniques such as resistant plants, scouting, nutrition monitoring, and economic thresholds. Featuring an IPM team with decades of experience, nursery producers, and tree care providers will be able to take home practical skills and knowledge.
The department offers areas of emphasis in Horticultural Enterprise Management and Horticultural Science within a Plant and Soil Science Bachelor of Science degree. Following are a few highlights of our undergraduate program in 2002-2003.
The Plant and Soil Science degree program has nearly 100 students in the fall semester of 2003, of which almost one-half are horticulture students and another one-third are turfgrass students. Eighteen horticulture students graduated in 2003.
We believe that a significant portion of an undergraduate education in horticulture must come outside the classroom. In addition to the local activities of the Horticulture Club and field trips during course laboratories, students have excellent off-campus learning experiences. Here are the highlights of such opportunities in 2003.
The demand for graduates with M.S. or Ph.D. degrees in Horticulture, Entomology, Plant Pathology, Agricultural Economics, and Agricultural Engineering is high. Our M.S. graduates are being employed in the industry, Cooperative Extension Service, secondary and postsecondary education, and governmental agencies. Last year, there were nine graduate students in these degree programs conducting research directly related to the Kentucky nursery and landscape industry. Graduate students are active participants in the UK Nursery and Landscape research program and contribute significantly to our ability to address problems and opportunities important to the Kentucky nursery and landscape industry.
R.L. Geneve, S.T. Kester, C. Edwards, and S. Wells, Department of Horticulture
Although oaks are considered difficult to root from cuttings, it has been demonstrated that juvenile cuttings of oak root easily (2). There have been numerous attempts to manipulate the ability of oaks to root from cuttings by using etiolation (12), grafting mature scions onto seedling understocks (11), rooting epicormic shoots (5,10), and mound layering (4). These studies demonstrate that rooting in oaks can be enhanced if mature stock plants are subjected to rejuvenation. Currently, willow oak cultivars are being commercially propagated from cuttings obtained from juvenile stock plants. This demonstrates the commercial potential, but these cultivars were seedling selected rather than selected from mature hardy plants.
The objective of this research is to develop a clonal system for propagation of mature oaks by rejuvenation using a step-wise process that includes: 1) inducing somatic embryogenesis from mature acorns from which the ovules have been removed, 2) creating juvenile stock plants from germinated somatic embryos, and 3) rooting cuttings from these juvenile stock plants.
Acorn pieces from willow oak were collected in midsummer after normal ovule abortion. Disinfested acorn halves with the viable ovule removed (dates 8/5 and 8/15) or the embryo alone (dates 8/15 and 8/21) were placed on a combination of 2, 4-dichlorphenoxyacetic acid (2, 4-D) or naphthalene acetic acid (NAA) at 1, 5 and 10 µM plus benzlyadenine (BA) at 1 µM for 15 days before being moved to growth regulator-free medium for expression of somatic embryogenesis. Explants were cultured in Petri dishes containing MS medium (8) under cool white fluorescent lamps (PAR 60 µmol·sec-1·m-2) at 21°C.
Greenhouse-grown seedling willow oaks were produced in flats containing Metromix 350 for two or four months. Softwood cuttings were treated with an IBA quick dip (0, 5,000, and 10,000 ppm) and rooted under intermittent mist with bottom heat in the greenhouse. The percentage of rooted cuttings and the average number of roots per rooted cutting were evaluated after 30 days.
In willow oak, pollination occurs in early spring, but fertilization of the ovule is not completed until 15 months later. There are five ovules per acorn, but only one usually remains viable in the mature fruit (Figure 1). The tissue between the outer fruit wall (pericarp) and the ovule is diploid female in origin. It is not clear if it is fruit (mesocarp) or nucellar.
Figure 1. Viable and aborted ovules in 15-month-old willow oak.
Callus growth was achieved from acorn pieces treated with 5 mM 2,4-D plus 1 µm BA (Figure 2a). Callus has continued to proliferate, but to date no somatic embryos have formed. Embryo explants produced somatic embryos when treated with 5 or 10 µM NAA plus 1 µM BA (Figure 2b).
Figure 2. Callus and somatic embryogenesis in willow oak. A.) Callus production after 6 weeks in acorn tissue treated with 5 µM 2, 4-D plus 1 µM BA. B.) Somatic embryo production from zygotic embryo explants treated with 10 µM NAA plus 1 µM BA.
Cuttings taken from two- or four-month old stock plants rooted at high percentages when treated with 5,000 or 10,000 ppm IBA (Table 1). Roots per rooted cuttings increased with 10,000 ppm IBA.
Table 1. Adventitious rooting in greenhouse-grown seedling stock plants of willow oak. |
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IBA [ppm] |
2-month-old stock plants |
|
4-month-oldstock plants |
|||
Rooting % |
Roots per rooted cutting |
Rooting % |
Roots per rooted cutting |
|||
0 |
37.5bz |
1.9c |
|
43.4b |
2.6c |
|
5,000 |
64.2a |
3.3b |
|
73.9a |
5.8b |
|
10,000 |
70.8a |
9.2a |
|
78.3a |
9.5a |
|
z |
Means within a column with the same letter were not different |
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Somatic embryogenesis has been achieved in a number of oak species from either embryo or vegetative tissue (1). Most of the species evaluated to date are not hardy northern oaks, except for a preliminary report in Q. rubra (9) using seedling leaves and a study in Q. bicolor (3). The report with Q. bicolor is especially important because it involved somatic embryo formation from male catkins. Recently, Merkle and Battle (7), using sweet gum (Liquidambar), have also demonstrated that flower tissue has a high capacity to form somatic embryos. Regeneration from flower parts represents a clonal form of regeneration from mature tissue, rather than the more typical "embryo cloning" found in somatic embryogenesis from zygotic seedling tissue reported for most woody plants.
Somatic embryogenesis would create a complete reversion from a mature state to a juvenile state as is achieved during normal zygotic embryogenesis (6). Somatic embryos derived from diploid female tissue (acorn sections) after removal of the ovules would be clonal. Therefore, if somatic embryogenesis is achieved from acorn-derived callus, the resultant plantlets would form juvenile stock plants suitable for cutting propagation. Work is ongoing to this end.
Oaks (Quercus spp.) are important nursery and forestry species. Most oaks are propagated by seeds because they are difficult to root from cuttings and many oaks experience delayed graft incompatibility. This severely limits availability of superior cultivars for the nursery trade. The ability to propagate superior mature clones of oak would result in increased selection and therefore profitability for oak liner and shade tree production. It would also allow growers to put existing oak cultivars on their own roots rather than attempting to graft these cultivars (i.e., Quercus palustris `Crown Right'). In addition, development of the proposed somatic embryogenesis system would provide an appropriate system for attempts to transform mature oaks with novel genes (i.e., any potential genes developed for disease resistance to oak wilt or bacterial leaf scorch).
Stephen Berberich, Robert Geneve, and Mark A. Williams, Department of Horticulture
Passion flowers (Passiflora sp.) have good market potential as high-value container-produced plants for patio or garden use, and selected cultivars can be successfully grown in Kentucky as a single-season crop using a two-month production scheme in an outdoor nursery (Figure 1) (1). However, cultural practices that reduce the time to flowering and increase overall flower production must be developed for this condensed production schedule.
Figure 1. Production schedule for single-season container-grown passion flowers in Kentucky.
Passion flower vines can produce a flower, shoot, and tendril at each node. In the majority of these plants, each flower opens for only one day. Once the vines start blooming, developing shoots can produce a flower at each node resulting in numerous flowers per plant each day (2). It becomes apparent that the flowering potential of each plant increases by increasing the number of nodes per plant. The objective of the current research was to investigate pinching treatments on time to first flower, number of nodes, and number of flowers per plant.
Between July 26, 2002, and October 16, 2002, two passion flower cultivars (Passiflora `Lady Margaret' and `Amethyst') were evaluated for flowering response following six pinching treatments. Passiflora `Lady Margaret' and `Amethyst' were propagated from two node cuttings treated with indole-3-butyric acid (IBA) (1,000 ppm in talc) and stuck in Oasis rooting cubes. Cuttings were placed in an intermittent mist bed (5 sec. every 10 min.) with bottom heat (75°F). After 21 days, cuttings were transferred to the greenhouse in 5-quart containers (Nursery Supplies, Inc. Classic 500) in Barky Beaver (Professional Grow Mix, Moss, Tennessee 38574) southern pine bark substrate and irrigated each day with 100 ppm N (Peters 20-10-20). Day/night temperatures in the greenhouse were set at 77°F/68°F (25ºC/20ºC ), and supplemental lighting (61 µmol · m-2 · sec-1 average photosynthetic photon flux density at bench top) was used to maintain 17-hour day length.
Initial pinching treatments were all performed 21 days after rooted cuttings were potted and secondary pinching treatments 42 days after cuttings were potted. The pinching treatments consisted of the following: 1) pinch the main shoot at the third node, 2) sixth node, 3) ninth node, 4) third node with all resulting shoots pinched at third node, 5) sixth node with all resulting shoots pinched at the sixth node, and 6) no pinching. Flowers were counted each day, and number of shoots, shoot length, and number of nodes were recorded 45 days after applying the first pinching treatment.
Both cultivars exhibited strong apical dominance and, when pinched, one of the resulting shoots assumed dominance. None of the pinching treatments increased the number of shoots, and both cultivars showed delayed flowering of approximately three weeks when pinched once and approximately four weeks when pinched twice (Figure 2).
Figure 2. Cumulative number of flowers per day for Passiflora `Amethyst' and `Lady Margaret' beginning on the day pinching treatments were performed. For both cultivars, flowering was delayed approximately three weeks when pinched one time and four weeks when pinched two times.
Amethyst passion flower pinched once produced 67% fewer flowers compared to non-pinched plants, and those pinched twice produced 88% fewer flowers. Lady Margaret passion flower pinched once produced 65% fewer flowers compared to non-pinched plants, and those pinched twice produced 89% fewer flowers (Table 1).
For both cultivars tested, pinching resulted in fewer shoots, fewer flowers, and delayed flowering. Cytokinin treatments are currently being tested to determine if they can be used effectively to induce branching. Additionally, the use of multiple plants per container has proven to be an excellent method for increasing the number of shoots and flowers, and this method eliminates the need to overcome the strong apical dominance exhibited by these plants.
Table 1. Mean number of shoots, shoot length, number of nodes, and number of flowers for Passiflora ‘Amethyst’ and ‘Lady Margaret’ 45 days after applying initial pinching treatments. |
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Pinch Treatment |
P. 'Amethyst' |
|
P. 'Lady Margaret' |
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Mean number of shoots |
Mean shoot length (cm) |
Mean number of nodes |
Mean number of flowers |
Mean number of shoots |
Mean shoot length (cm) |
Mean number of nodes |
Mean number of flowers |
|||
No pinch |
10.1 az |
969.0 ab |
177.7 a |
16.5 a |
|
7.4 a |
560.9 a |
113.6 a |
17.9 a |
|
Pinched at node 3 |
7.3 b |
890.5 ab |
154.8 ab |
0.6 b |
5.0 b |
412.1 ab |
70.1 b |
3.3 bc |
||
Pinched at node 6 |
8.3 ab |
1070.0 a |
193.2 a |
2.9 b |
5.8 ab |
517.6 a |
101.8 ac |
8.8 b |
||
Pinched at node 9 |
7.1 b |
863.9 ab |
163.8 ab |
12.7 a |
5.8 ab |
559.2 a |
113.0 a |
6.8 bc |
||
Pinched at node 3 & 3 |
6.8 b |
700.4 b |
120.6 b |
0.9 b |
4.8 b |
300.1 b |
54.9 b |
0.6 c |
||
Pinched at node 6 & 6 |
7.8 b |
1048.2 a |
188.8 a |
3.4 b |
4.9 b |
410.2 ab |
87.3 bc |
2.8 bc |
||
z |
Means within a column for each cultivar followed by the same letter are not significantly different as determined by Tukey’s test at P < 0.05. |
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This is the third report on studies carried out to evaluate the production of container-grown passion flowers. This study has shown that selected varieties can be successfully grown in Kentucky as a single-season crop using standard nursery practices with the two-month production schedule presented in this paper. These plants have good potential as a high-value container-produced plant for patio or garden use in a market where customers are looking for exotic, tropical vines.
Amy Fulcher, Matt Ernst, and Robert McNiel, Departments of Horticulture and Agricultural Economics
Nature of Work
Pot-in-Pot production is growing in interest in Kentucky. Pot-in-Pot production often requires a considerable capital investment. Therefore, growers need production budgets and estimated cash flows available to them to help estimate the installation and production costs, as well as potential returns, from plants grown in Pot-in-Pot systems. This economic information is essential in order to make informed production decisions.
Red maple cultivars such as Red Sunset and October Glory are trees in demand and are commonly grown in Pot-in-Pot production systems. A trade 15 gallon is the most commonly produced size in Pot-in-Pot systems. Therefore, the budgets and price sensitivity charts were created for a red maple cultivar in a 15-gallon container.
Two sets of production budgets, 10-year cash flow estimates, and rudimentary price sensitivity analyses were developed based on two different production scenarios using cost information developed from demonstration plots. The first production scenario utilized a $15 bareroot liner (Table 1). This input would represent a very high quality liner. A high quality liner is the foundation of a high quality plant, which would receive the highest price on the wholesale market. It is difficult or impossible to grow a high quality tree from a poor-quality liner. As is expected, these estimates indicate that producing higher quality trees could be significantly more profitable in a 10-year period.
Table 1. Estimated cash flows for 1 acre of 15-gallon red maple cultivar in pot-in-pot production.* |
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Liners purchased for $15 each, finished trees sold for $50 each. See price sensitivity chart for other sales prices. |
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1,144 trees planted per acre |
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1,087 trees marketed per acre |
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EXPENSES |
Year 1 |
Year 2 |
Year 3 |
Year 4 |
Year 5 |
Year 6 |
Year 7 |
Year 8 |
Year 9 |
Year 10 |
|
INSTALLATION EXPENSE |
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1,144 sockets @$20 |
$22,880 |
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|
|
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Fabric |
$1,694 |
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|
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Irrigation system1 |
$8,276 |
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|
|
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|
|
|
|
|
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Total Installation Expense |
$32,850 |
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PLANTING EXPENSE |
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Plant liners @$15 |
$17,160 |
|
$17,160 |
|
$17,160 |
|
$17,160 |
|
$17,160 |
|
|
Insert pots @$3.30 |
$3,775 |
|
$3,775 |
|
$3,775 |
|
$3,775 |
|
$3,775 |
|
|
Hired labor–10 min./tree @$10/hr |
$1,907 |
|
$1,907 |
|
$1,907 |
|
$1,907 |
|
$1,907 |
|
|
Media (76 cu. yd. @$20) |
$1,520 |
|
$1,520 |
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$1,520 |
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$1,520 |
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$1,520 |
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Bamboo stakes @$1.62 |
$1,853 |
|
$1,853 |
|
$1,853 |
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$1,853 |
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$1,853 |
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Tying ribbon |
$10 |
|
$10 |
|
$10 |
|
$10 |
|
$10 |
|
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Equipment fuel, oil, repairs2 |
$18 |
|
$18 |
|
$18 |
|
$18 |
|
$18 |
|
|
Total Planting Expense |
$26,244 |
|
$26,244 |
|
$26,244 |
|
$26,244 |
|
$26,244 |
|
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ANNUAL PRODUCTION EXPENSE |
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Pesticides5 |
$12 |
$12 |
$12 |
$12 |
$12 |
$12 |
$12 |
$12 |
$12 |
$12 |
|
Irrigation2 |
$36 |
$36 |
$36 |
$36 |
$36 |
$36 |
$36 |
$36 |
$36 |
$36 |
|
Hired labor |
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Pruning: 30 min./tree @$10/hr |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
|
Maintenance: 30 min./tree @$10/hr |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
|
Equipment fuel, oil, repairs2 |
$13 |
$13 |
$13 |
$13 |
$13 |
$13 |
$13 |
$13 |
$13 |
$13 |
|
Total Production Expense |
$11,502 |
$11,502 |
$11,502 |
$11,502 |
$11,502 |
$11,502 |
$11,502 |
$11,502 |
$11,502 |
$11,502 |
|
HARVEST EXPENSE |
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Equipment fuel, oil, repairs2 |
|
$27 |
|
$27 |
|
$27 |
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$27 |
|
$27 |
|
Hired labor–5 min./tree @$10/hr |
|
$953 |
|
$953 |
|
$953 |
|
$953 |
|
$953 |
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Marketing expense (2% of gross sales) |
|
$2,174 |
|
$2,174 |
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$2,174 |
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$2,174 |
|
$2,174 |
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Total Harvest Expense |
|
$3,154 |
|
$3,154 |
|
$3,154 |
|
$3,154 |
|
$3,154 |
|
TOTAL CASH EXPENSE |
$70,595 |
$14,656 |
$37,745 |
$14,656 |
$37,745 |
$14,656 |
$37,745 |
$14,656 |
$37,745 |
$14,656 |
|
SALES |
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1,087 trees @$100 |
|
$108,700 |
|
$108,700 |
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$108,700 |
|
$108,700 |
|
$108,700 |
|
GROSS SALES |
|
$108,700 |
|
$108,700 |
|
$108,700 |
|
$108,700 |
|
$108,700 |
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ANNUAL CASH FLOW3 |
$(70,595) |
$94,044 |
$(37,745) |
$94,044 |
$(37,745) |
$94,044 |
$(37,745) |
$94,044 |
$(37,745) |
$94,044 |
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CUMULATIVE CASH FLOW4 |
$(70,595) |
$23,449 |
$(14,297) |
$79,747 |
$42,002 |
$136,046 |
$98,300 |
$192,344 |
$154,599 |
$248,643 |
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Cost and Return per Plant |
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Installation cost |
$28.72 |
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Planting cost |
22.94 |
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Annual production cost |
10.05 |
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Harvest cost |
2.76 |
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|
9% |
18% |
27% |
34% |
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Net Present Value of Cash Flows |
$132,304 |
$74,215 |
$42,470 |
$27,190 |
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1 |
Irrigation system is assumed to be purchased in Year 1 (new purchase price: $2,476–system controller/lines; $1,800–pump; $4,000–filters and PVC). |
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2 |
Assumes existing ownership of 34HP tractor (new purchase price: $18,000) and wagon (new purchase price: $1,241). |
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3 |
Annual cash flow is the amount available for loan principal and interest repayment, operator management and labor, depreciation, and other fixed costs. |
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4 |
Cumulative cash flow is the present value of accumulated cash flows. |
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5 |
Some cultivars will require substantially more pesticide applications. |
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* |
Check <http://www.uky.edu/Ag/HortBiz/pubs.html#budgets> for interactive budgets. |
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The second production scenario (Table 3) utilized a $7 bareroot liner. This liner is likely of a lower quality and may have scars or other damage on the trunk, a crooked trunk, and/or a poor branching structure. As a finished tree, this plant would not likely be saleable in the most profitable markets due to reduced quality. No price discounts are reflected in the cost of the liners because one acre of production would not be a substantial enough volume to garner significant discounts. However, an established field producer converting or adding Pot-in-Pot production may have sufficient quantity for price discounts. All other costs are the same.
The production cycle for both scenarios involves planting a 5-foot lightly branched liner in the spring of odd years and harvesting 95% (1,087) of the 1,144 trees planted in the one-acre system in even years. Finished trees are sold at 1.5 inch caliper. The budget accounts for 5% of the 1,144 trees dying during production. New growers may want to increase the percentage of loss if they have inadequate cold storage or receive poor quality liners. No trees are carried over to another year or repotted into a larger size.
Table 3. Estimated cash flows for 1 acre of red maple cultivar pot-in-pot production.* |
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Liners purchased for $7 each, finished trees sold for $50 each. See price sensitivity chart for other sales prices. |
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1,144 trees planted per acre |
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1,087 trees marketed per acre (5% mortality rate) |
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EXPENSES |
Year 1 |
Year 2 |
Year 3 |
Year 4 |
Year 5 |
Year 6 |
Year 7 |
Year 8 |
Year 9 |
Year 10 |
|
INSTALLATION EXPENSE |
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1,144 sockets @$20 |
$22,880 |
|
|
|
|
|
|
|
|
|
|
Fabric |
$1,694 |
|
|
|
|
|
|
|
|
|
|
Irrigation system1 |
$8,276 |
|
|
|
|
|
|
|
|
|
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Total Installation Expense |
$32,850 |
|
|
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|
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PLANTING EXPENSE |
|||||||||||
Plant liners @$7 |
$8,008 |
|
$8,008 |
|
$8,008 |
|
$8,008 |
|
$8,008 |
|
|
Insert pots @$3.30 |
$3,775 |
|
$3,775 |
|
$3,775 |
|
$3,775 |
|
$3,775 |
|
|
Hired labor–10 min./tree @$10/hr |
$1,907 |
|
$1,907 |
|
$1,907 |
|
$1,907 |
|
$1,907 |
|
|
Media (76 cu. yd. @$20) |
$1,520 |
|
$1,520 |
|
$1,520 |
|
$1,520 |
|
$1,520 |
|
|
Bamboo stakes @$1.62 |
$1,853 |
|
$1,853 |
|
$1,853 |
|
$1,853 |
|
$1,853 |
|
|
Tying ribbon |
$10 |
|
$10 |
|
$10 |
|
$10 |
|
$10 |
|
|
Equipment fuel, oil, repairs2 |
$18 |
|
$18 |
|
$18 |
|
$18 |
|
$18 |
|
|
Total Planting Expense |
$17,092 |
|
$17,092 |
|
$17,092 |
|
$17,092 |
|
$17,092 |
|
|
|
|||||||||||
ANNUAL PRODUCTION EXPENSE |
|||||||||||
Pesticides5 |
$12 |
$12 |
$12 |
$12 |
$12 |
$12 |
$12 |
$12 |
$12 |
$12 |
|
Irrigation2 |
$36 |
$36 |
$36 |
$36 |
$36 |
$36 |
$36 |
$36 |
$36 |
$36 |
|
Hired labor |
|
|
|
|
|
|
|
|
|
|
|
Pruning: 30 min./tree @$10/hr |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
|
Maintenance: 30 min./tree @$10/hr |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
$5,720 |
|
Equipment fuel, oil, repairs2 |
$13 |
$13 |
$13 |
$13 |
$13 |
$13 |
$13 |
$13 |
$13 |
$13 |
|
Total Production Expense |
$11,502 |
$11,502 |
$11,502 |
$11,502 |
$11,502 |
$11,502 |
$11,502 |
$11,502 |
$11,502 |
$11,502 |
|
|
|||||||||||
HARVEST EXPENSE |
|||||||||||
Equipment fuel, oil, repairs2 |
|
$27 |
|
$27 |
|
$27 |
|
$27 |
|
$27 |
|
Hired labor–5 min./tree @$10/hr |
|
$953 |
|
$953 |
|
$953 |
|
$953 |
|
$953 |
|
Marketing expense (2% of gross sales) |
|
$1,087 |
|
$1,087 |
|
$1,087 |
|
$1,087 |
|
$1,087 |
|
Total Harvest Expense |
|
$2,067 |
|
$2,067 |
|
$2,067 |
|
$2,067 |
|
$2,067 |
|
|
|||||||||||
TOTAL CASH EXPENSE |
$61,443 |
$13,569 |
$28,593 |
$13,569 |
$28,593 |
$13,569 |
$28,593 |
$13,569 |
$28,593 |
$13,569 |
|
|
|||||||||||
SALES |
|
|
|
|
|
|
|
|
|
|
|
1,087 trees marketed @$50 |
|
$54,350 |
|
$54,350 |
|
$54,350 |
|
$54,350 |
|
$54,350 |
|
|
|||||||||||
GROSS SALES |
|
$54,350 |
|
$54,350 |
|
$54,350 |
|
$54,350 |
|
$54,350 |
|
|
|
|
|
|
|
|
|
|
|
|
|
ANNUAL CASH FLOW3 |
$(61,443) |
$40,781 |
$(28,593) |
$40,781 |
$(28,593) |
$40,781 |
$(28,593) |
$40,781 |
$(28,593) |
$40,781 |
|
|
|
|
|
|
|
|
|
|
|
|
|
CUMULATIVE CASH FLOW4 |
$(61,443) |
$(20,662) |
$(49,256) |
$(8,475) |
$(37,068) |
$3,713 |
$(24,881) |
$15,900 |
$(12,693) |
$28,088 |
|
Cost and Return per Plant |
|
|
|
|
|
|
|
|
|
|
|
Installation Cost |
$28.72 |
|
|
|
|
|
|
|
|
|
|
Planting cost |
14.94 |
|
|
|
|
|
|
|
|
|
|
Annual production cost |
10.05 |
|
|
|
|
|
|
|
|
|
|
Harvest cost |
1.81 |
|
|
|
|
|
|
|
|
|
|
|
2% |
5% |
7% |
9% |
|
|
|
|
|
|
|
Net Present Value of Cash Flows |
$19,447 |
$9,236 |
$3,860 |
($616) |
|
|
|
|
|
|
|
1 |
Irrigation system is assumed to be purchased in Year 1 (new purchase price: $2,476–system controller/lines; $1,800–pump; $4,000–filters and PVC). |
||||||||||
2 |
Assumes existing ownership of 34HP tractor (new purchase price: $18,000) and wagon (new purchase price: $1,241). |
||||||||||
3 |
Annual cash flow is the amount available for loan principal and interest repayment, operator management and labor, depreciation, and other fixed costs. |
||||||||||
4 |
Cumulative cash flow is the present value of accumulated cash flows. |
||||||||||
5 |
Some cultivars will require substantially more insecticide applications. |
||||||||||
* |
Check <http://www.uky.edu/Ag/HortBiz/pubs.html#budgets> for interactive budgets. |
||||||||||
Based on these estimates it is imperative that growers marketing to smaller, lower priced, wholesale markets (i.e., most local and regional markets in and around Kentucky) and control the cost of liners and other inputs to realize a profit. While $15 liners may be grown into $100 wholesale trees, new growers without sufficient production volume or established quality may not be able to sell to the larger, higher quality markets. Projected annual cash flow at various sales prices for systems with $15-liner and $7-liner inputs are provided in Tables 2 and 4, respectively. Growers who sell trees locally or regionally are likely competing with established producers from more southern climates who are able to acquire cheaper land and labor and take advantage of a longer growing season. Therefore, these growers may need to consider carefully various input costs when developing marketing plans and making purchasing decisions, such as liner quality and cost. In addition, the amount of labor spent on pruning and controlling pests will vary depending on the intended market and probable wholesale price to realize a profit.
Table 2. Price sensitivity chart: Annual cash flows at various prices. |
|||||||||||
Liners purchased for $15 each. |
|||||||||||
1,087 trees |
Cumulative Cash Flow (Not Discounted) |
||||||||||
Year |
|||||||||||
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
||
$50 |
$(70,595) |
$39,694 |
$(37,745) |
$39,694 |
$(37,745) |
$39,694 |
$(37,745) |
$39,694 |
$(37,745) |
$39,694 |
$(23,107) |
$60 |
$(70,595) |
$50,564 |
$(37,745) |
$50,564 |
$(37,745) |
$50,564 |
$(37,745) |
$50,564 |
$(37,745) |
$50,564 |
$31,243 |
$70 |
$(70,595) |
$61,434 |
$(37,745) |
$61,434 |
$(37,745) |
$61,434 |
$(37,745) |
$61,434 |
$(37,745) |
$61,434 |
$85,593 |
$75 |
$(70,595) |
$66,869 |
$(37,745) |
$66,869 |
$(37,745) |
$66,869 |
$(37,745) |
$66,869 |
$(37,745) |
$66,869 |
$112,768 |
$80 |
$(70,595) |
$72,304 |
$(37,745) |
$72,304 |
$(37,745) |
$72,304 |
$(37,745) |
$72,304 |
$(37,745) |
$72,304 |
$139,943 |
$90 |
$(70,595) |
$83,174 |
$(37,745) |
$83,174 |
$(37,745) |
$83,174 |
$(37,745) |
$83,174 |
$(37,745) |
$83,174 |
$194,293 |
$100 |
$(70,595) |
$94,044 |
$(37,745) |
$94,044 |
$(37,745) |
$94,044 |
$(37,745) |
$94,044 |
$(37,745) |
$94,044 |
$248,643 |
Table 4. Price sensitivity chart: Annual cash flows at various prices. |
|||||||||||
Liners purchased for $7 each. |
|||||||||||
1,087 |
trees |
Cumulative Cash Flow (Not Discounted) |
|||||||||
Year |
|||||||||||
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
||
$45 |
$(61,443) |
$35,346 |
$(28,593) |
$35,346 |
$(28,593) |
$35,346 |
$(28,593) |
$35,346 |
$(28,593) |
$35,346 |
$913 |
$50 |
$(61,443) |
$40,781 |
$(28,593) |
$40,781 |
$(28,593) |
$40,781 |
$(28,593) |
$40,781 |
$(28,593) |
$40,781 |
$28,088 |
$55 |
$(61,443) |
$46,216 |
$(28,593) |
$46,216 |
$(28,593) |
$46,216 |
$(28,593) |
$46,216 |
$(28,593) |
$46,216 |
$55,263 |
$60 |
$(61,443) |
$51,651 |
$(28,593) |
$51,651 |
$(28,593) |
$51,651 |
$(28,593) |
$51,651 |
$(28,593) |
$51,651 |
$82,438 |
$70 |
$(61,443) |
$62,521 |
$(28,593) |
$62,521 |
$(28,593) |
$62,521 |
$(28,593) |
$62,521 |
$(28,593) |
$62,521 |
$136,788 |
Producers need decision-making tools in order to make sound business decisions. These production budget estimates allow growers to consider the capital investment required to set up a Pot-in-Pot production system on a per acre basis. In addition, the cash flow estimates and price sensitivity analyses illustrate the power of growing high quality plants and selling in a more lucrative, high quality market, as well as the need to keep costs low when selling into a lower priced market. These, and any other budget estimates, are useless if the market is not analyzed and identified before a nursery system is established and production begins.
Note: These estimates represent generic estimates and should be used only as a guideline for decision making. All financial decisions should be analyzed with regard to individual production scenarios and market outlooks.
Jamee L. Hubbard and Daniel A. Potter, Department of Entomology
Calico scale, Eulecanium cerasorum, is a pest of a variety of woody plants in urban landscapes. Calico scale was apparently introduced into the San Francisco, California, area in the early 1900s from Asia and has since spread to Kentucky and surrounding states through the transport of infested plant material. In recent years, calico scale has reached outbreak proportions in urban areas of Central Kentucky on maples, honeylocust, sweet gum, hackberries, and many other tree species. The scale encrusts the branches and covers the leaves of trees. This pest is a phloem feeder, and in large numbers, feeding can result in branch and limb dieback. Trees may be directly killed by calico scale feeding or severely weakened, consequently succumbing to woodborer attacks, drought, or other stresses. It produces copious amounts of honeydew, which may coat automobiles and other objects under infested trees. Honeydew encourages growth of sooty mold fungus that blackens foliage and bark and may interfere with photosynthesis.
During the past five years, severe outbreaks of this pest have occurred on Central Kentucky horse farms, golf courses, and street plantings. The impact of this outbreak is extensive because there has been little research on the pest's biology or management.
Earlier research determined the best management practices that would be useful in sensitive areas, such as horse farms. The focus of our research in 2003 was to determine the impact that two types of management practices—foliar sprays and systemic trunk injection—shave on calico scale and generalist predators in the tree canopy.
We conducted an experiment on a local horse farm, testing three insecticides and two application methods to target first-instar settled crawlers in late spring and early summer. A pyrethroid spray (bifenthrin, Talstar® F Insecticide/Miticide) was applied with a pressurized sprayer to the entire canopy of five sweetgum trees, Liquidambar styraciflua, along two fencerows on 02 July 2003. The spray solution included Breakthrough® spreader/sticker at a rate of 0.31 ml per liter solution. A systemic organophosphate (bidrin, Mauget Inject-a-cide B™) was injected into the trunks of five sweetgum trees on 02 July 2003, and a systemic chloronicotinyl (imidacloprid, Mauget Imicide®) was injected into the trunks of five sweetgum trees on 28 May, 2003. Insecticides were applied at a rate listed to control scale insects. Five trees were left untreated.
Twenty-five leaves per tree were collected on 07 August 2003 to determine the impact of insecticides on calico scale. Live and dead crawlers were counted, and percent calico scale mortality was determined by comparing number of dead crawlers with total number of crawlers. To determine the impact of the insecticides on generalist predators in the canopy, eight branch samples were taken from each tree every two weeks, starting one day before treatment and ending on 30 September 2003. To obtain branch samples, a 60- x 40-cm plastic bag was quickly slipped over the branch and cinched at the open end. Approximately 40 cm of the terminal branch was removed from the tree. The samples were frozen, and arthropods were identified to family, class, or order. Predatory arthropod groups that were analyzed included adults and larvae from the family Coccinellidae (ladybird beetles), adults, and larvae of the order Neuroptera (lacewings), members of the class Araneae (spiders), and adults of the family Formicidae (ants). Numbers of predatory arthropods were compared for each treatment across the season.
Talstar® foliar sprays yielded an average crawler mortality of 54% and was significantly different from the untreated control (p = 0.018), whereas bidrin trunk injections yielded an average crawler mortality of 39% and was not significantly different from the control (Figure 1). Imicide® also did not significantly control calico scale crawlers.
Figure 1. Average percent crawler mortality on sweetgum trees.
Both Talstar® and bidrin had a significant but short-term impact on predators in the tree canopy. Spiders were impacted the most with a significant reduction in populations for up to four weeks after the application of Talstar® foliar sprays and up to two weeks after application of bidrin trunk injections. Ants also had a significant reduction in populations for up to two weeks with both Talstar® and bidrin applications. Lacewings and ladybird beetles, both highly mobile predators, were not significantly impacted by any insecticide treatment in the experiment. The impact on predator populations was a little less severe with bidrin trunk injections than with Talstar® canopy sprays.
The objective of this project was to determine the impact of three insecticide treatments, involving two application techniques, on calico scale crawlers and on generalist predators in the tree canopy. We demonstrated that two popular products used to control calico scale, Talstar® foliar sprays and bidrin trunk injections, have only a short-term impact on predators in the canopy. The efficacy data combined with the predator impact data will be valuable in helping ornamental pest managers make decisions in the management of calico scale. Additional research is currently under way to assess the impact these insecticide treatments have on the parasitoid complex associated with calico scale and rate of parasitism in calico scale.
Daniel A. Potter, Leslie Foss, and David W. Held, Department of Entomology
An equine disease now known as Mare Reproductive Loss Syndrome (MRLS) struck the Ohio Valley in 2001-2002, causing thousands of foal abortions and catastrophic economic loss. Evidence that pregnant mares' exposure to eastern tent caterpillars (ETC), Malacosoma americanum (F.), induces MRLS created an urgent call for caterpillar control on or near horse farms. Many tree care professionals now are providing that service. We surveyed egg mass distribution and monitored ETC emergence in wild cherry trees to help guide control actions and evaluated reduced-risk treatment strategies, including foliage sprays, trunk injections, winter egg mass treatments, and barrier sprays, to intercept larvae entering pastures.
Emergence of ETC from egg masses and subsequent colony development were monitored at several field locations in central Kentucky. Sites were rows of wild cherry trees bordering pastures or fences. Twigs bearing egg masses were tagged in mid-February and checked every 1 to 2 days until mid-April, when emergence of larvae had ceased. Duration of emergence from individual egg masses was determined, as well as number of ETC per mass. Larval behavior (e.g., aggregation on egg masses, movement to twigs, size of nests) and instars predominating were noted. Distribution of egg masses within tree canopies (height, cardinal direction, open versus sheltered side of tree, distance of mass from shoot tip, diameter of twigs bearing masses) was surveyed for 10 mature wild cherry trees.
Potential for winter control of eggs was evaluated by spraying tagged egg masses with bifenthrin or permethrin formulated in a penetrating solvent, dormant oil, or oil/insecticide mixtures in December or February and then evaluating effects by dissecting some egg masses and monitoring others for larval emergence in early spring. Residual effects of such treatments were measured by placing young ETC larvae on the surface of treated egg masses.
Reduced-risk insecticides applied as contact or foliage sprays were extensively evaluated against both newly hatched and late instar ETC. Speeds of kill, residual effectiveness, and potential for repellence of larvae were tested. Treatments included horticultural oil, insecticidal soap, bifenthrin, Bacillus thuringiensis, spinosad, and tebufenozide (a molt-accelerating compound).
Trunk microinjection is a process wherein small amounts of therapeutic chemicals contained in sealed capsules are introduced into small shallow holes drilled around the base of a tree (Tattar et al. 1998). It seemingly is well suited for use on horse farms and suburban landscapes because it eliminates spray drift, reduces hazard and environmental exposure, and can be performed under most weather conditions. Effectiveness of microinjection for controlling ETC was evaluated in four separate trials conducted on horse farms, using treatment timings ranging from before egg hatch (early March) to late April, when large caterpillars were present in trees. Four systemic insecticides, bidrin, abamectin, milbemectin, and emamectin benzoate were evaluated. Nests were harvested by climbing trees, or with a pole pruner, and dissected to determine proportion of dead or live larvae.
Barrier treatments applied to pasture grass to intercept wandering late-instar larvae also were evaluated. Treatments included permethrin, malathion, and carbaryl. For permethrin, the most effective treatment, the residual effectiveness and distance larvae could crawl across treated areas also was determined.
Egg masses were concentrated in the lower canopy, on the exposed sides of trees, on twigs averaging 3.7mm diameter (range 2.1 to 5.7mm), and at mean distance of 17.9 cm (range 8.3 to 36.2 cm) from shoot tips. Larval emergence began in mid-March in both 2002 and 2003, coinciding with about 50% bloom of Forsythia intermedia Zabel. Emergence was extended over three to four weeks in 2002, a year with typical March temperatures but more compressed (7 to 10 days) in 2003 due to unseasonably warm temperatures.
Winter treatment of egg masses with bifenthrin or permethrin in a penetrating solvent prevented emergence, but 3% horticultural oil was ineffective for that purpose. The pyrethroids also killed young larvae placed on treated egg masses and twigs. Therefore, neonates that manage to emerge (e.g., from egg masses that receive incomplete spray coverage) likely would be killed before they initiate a nest.
Insecticidal soap or oil gave relatively poor control even when sprayed directly on neonates. Foliage sprays with bifenthrin and spinosad were highly effective against all instars, their field-weathered residues remaining active for at least seven days. Bacillus thuringiensis controlled neonates within three days but was slower acting and less active against late instars, with shorter residual than bifenthrin or spinosad. Given its relatively short residual, several weekly applications starting a few days after first egg hatch likely would be needed for a high level of control. Insecticide residues did not repel larvae.
Microinjection of cherry trees with bidrin was highly effective against all instars, whereas injections with milbemectin or abamectin gave poor or less consistent control. Trunk injection with emamectin benzoate was effective in the one trial in which it was evaluated.
Dry residues of permethrin controlled late instars crawling in pasture grass for at least seven days, but malathion or carbaryl were ineffective for that purpose.
The discovery in 2002 that exposure to ETC induces abortions consistent with Mare Reproductive Loss Syndrome created a climate of near-zero tolerance for ETC and an urgent call for non-hazardous control tactics. This research provides options that the arboricultural and equine industries can immediately put to use.
Bifenthrin was the fastest-acting, most effective foliage treatment we tested, field-weathered spray residues remaining active for least a week. Applied two to three weeks after first egg hatch, it can provide tree-wide control with one application. The formulation we evaluated (Talstar F®) recently was replaced by an equivalent new product, TalstarOne®, that is labeled for tree-feeding caterpillars including ETC. Bacillus thuringiensis (Dipel®) also was effective, although more so against young larvae than against older ones. Given its relatively short residual, several weekly applications starting a few days after first egg hatch likely would be needed for a high level of control. Both the Environmental Protection Agency's 1992 Worker Protection Standard and label grazing restrictions limit the choice of insecticides that can be applied to trees on horse farms. Labels for bifenthrin (TalstarOne®) and B. thuringiensis allow such use.
The bifenthrin formulation we evaluated for winter control of egg masses recently received EPA registration as Onyx® (FMC, Philadelphia, PA). Both permethrin (Astro®) and bifenthrin (Onyx®) are labeled for use on trees, permitting targeting of ETC egg masses in winter (Long, J., 2003, pers. comm). Because living and old egg masses are difficult to distinguish from the ground, treating whole trees to control egg masses likely would be less efficient than targeting nests with young larvae in early spring. Winter egg mass treatments may, however, be justified in years when ETC populations are at outbreak level and risk of MRLS is high.
Microinjection with bidrin (as Inject-a-cide B®) was highly effective in controlling ETC and is labeled for that purpose. Bidrin is a Restricted Use Pesticide due to acute oral and dermal toxicity, although microinjection allows certified applicators to use it with low hazard. Optimal timing is when small nests first appear in the trees. Bidrin also was effective against larger tents and larvae.
A 2-m sprayed band of Astro® insecticide (permethrin) just outside the fence line should be effective in intercepting wandering larvae. Some arborists and horse farm managers also reported success with permethrin applied to grass around the base of trees.
ETC outbreaks are cyclic, and populations have been declining since 2001 and 2002. Horse farm managers and arborists should remain vigilant, however, as recent research continues to implicate pregnant mares' exposure to ETC as inducing abortions and ETC will continue to be present at moderate levels every year, gradually building through to the next outbreak cycle.
Michael E. Rogers and Daniel A. Potter, Department of Entomology
The purpose of this project is to evaluate whether providing supplemental food sources in the form of high nectar-producing plants or sugar sprays will increase parasitism of turf-infesting white grubs by tiphiid wasps. By providing such food sources, it may be possible to attract these beneficial insects to an area, leading to increased grub parasitism. Planting nectar-producing perennials might then be recommended to homeowners or golf course superintendents as a sustainable approach to help control white grubs without relying as heavily on pesticides.
Tiphiid wasps are the primary group of parasitoids that attack white grubs. These wasps spend most of their time searching for grubs in the soil and surface only to mate and obtain food in the form of honeydew or nectar from flowers. In the 1920s and '30s, Tiphia vernalis, a parasite of Japanese beetle grubs, was imported from Japan as a potential biological control agent. It later was observed that the locations where the wasp became established seemed to be ones with abundant nearby food sources. However, no further work was done to confirm that nectar-producing plants encourage these natural enemies. We have found Tiphia vernalis to be locally abundant in Kentucky, parasitizing Japanese beetle grubs from early May through mid-June. We also discovered a native Tiphia species, Tiphia pygidialis Allen, that attacks masked chafer grubs from August until early October.
To verify potential benefits of supplemental carbohydrates, adult females of each parasite species were maintained in the lab, and their longevity and fecundity was compared between individuals provided 10% sugar water versus water only. Gardens of spring- or fall-blooming flowering plants were established and monitored several times per week to determine if particular plant species attract Tiphia spp.
Two field experiments were conducted. In the first, grubs were implanted into turf plots and then those plots, or adjacent turf areas, were sprayed with 10% sugar water to attract Tiphia wasps. Grubs later were dug up to compare parasitism rates. In the second study, plantings of peonies (which were found to attract T. vernalis) were established in a large stand of Kentucky bluegrass, and Japanese beetle grubs were implanted at varying distances away. Numbers of wasps visiting the peonies were monitored. At the end of wasp flight, the turf was sampled and the incidence of parasitism was determined in relation to distance from the nectar source.
Survival of spring-active Tiphia vernalis and late summer-active Tiphia pygidialis was significantly increased when wasps were provided with 10% sugar water in the laboratory, confirming that access to carbohydrates benefits the wasps. Presence of a grub for host feeding (i.e., taking a blood meal) did not affect wasp longevity. Tiphia pygidialis, the parasite of masked chafers, was never observed feeding on flowers in the fall-blooming gardens. However, hundreds of the wasps visited turf sprayed with 10% sugar water to feed. Parasitism by T. pygidialis was significantly elevated (from 9% to 45%) in turf plots located near sugar-sprayed turf. Interestingly, parasitism was reduced in the turf that was directly sprayed, evidently because wasps attracted to those plots spent their time feeding rather than searching for grubs in the soil.
Tiphia vernalis, the Japanese beetle parasite, was never observed feeding on sugar-sprayed turf, nor did such treatments affect its parasitism of grubs in or near sugar-sprayed turf. Numerous T. vernalis were, however, observed feeding on nectar from peony (Peonia lactiflora Pallas). When replicated plantings of P. lactiflora were established in a stand of turf, parasitism of P. japonica was significantly higher near the peonies. We also have observed hundreds of T. vernalis feeding on honeydew of aphids and soft-scale insects in trees such as oaks, maples, and the tulip tree and documented parasitism rates as high as 50% in golf course roughs adjacent to such trees.
This work suggests that incorporating peonies or similar nectar-producing flowers into home landscapes or on golf courses can help sustain populations of Tiphia vernalis and may increase parasitism and mortality of Japanese beetle grubs in adjacent turf. Trees (e.g., oaks and maples) that support non-harmful levels of aphids or other honeydew-producing insects also provide a food source for Tiphia populations. Incorporating such plants into home, commercial, and golf course landscapes can have benefits for conservation biological control of turf-infesting white grubs.
For full article, see Rogers, M.E. and D.A. Potter. 2004. Environ. Entomol. In Press.
Julie Beale, Paul Bachi, and John Hartman, Department of Plant Pathology
Plant disease diagnosis is an ongoing educational and research activity of the UK Department of Plant Pathology. We maintain two branches of the Plant Disease Diagnostic Laboratory, one on the UK campus in Lexington and one at the UK Research and Education Center in Princeton. Of the more than 4,000 plant specimens examined annually, about 40% are landscape plant specimens (1).
Making a diagnosis requires a great deal of research into the possible causes of the plant problem. Most visual diagnoses involve microscopy to determine what plant parts are affected and to identify the microbe involved. In addition, many specimens require special tests such as moist chamber incubation, culturing, enzyme-linked immunosorbent assay (ELISA), electron microscopy, nematode extraction, or soil pH and soluble salts tests. This year, the laboratory is using polymerase-chain-reaction (PCR) testing which, although very expensive, will allow more precise and accurate diagnoses. Computer-based laboratory records are maintained to provide information used for conducting plant disease surveys, identifying new disease outbreaks, and formulating educational programs. In addition, information from the laboratory forms the basis for timely news of landscape disease problems through the Kentucky Pest News newsletter, radio and television tapes, and plant health care workshops.
The 2003 growing season in Kentucky provided mostly cooler than normal temperatures and above normal rainfall. This season produced the second wettest April-August on record, and the second coolest June and July. January temperatures were below normal but not cold enough to cause widespread cold injuries to woody plants, although there was some injury. There were few significant late spring frosts to cause additional injury.
This year the following important diseases or diseases that were unusual or increased due to the wet weather were observed:
The first step in appropriate pest management in the landscape is an accurate diagnosis of the problem. The UK Plant Disease Diagnostic Laboratory assists the landscape industry of Kentucky in this effort. To serve their clients effectively, landscape industry professionals, such as arborists, nursery operators, and landscape installation and maintenance organizations, need to be aware of recent plant disease history and the implications for landscape maintenance. This report is a synopsis of the useful information about plant disease provided for landscape professionals.
John Hartman, Joe Collins, Carl Harper, Amy Fulcher, Claudia Cotton, Paul Vincelli, and Bernadette Amsden, Departments of Plant Pathology, Entomology, and Horticulture
During recent years, a new disease of oaks and other woody plants has appeared in the coastal regions of northern California and Oregon. The disease, sudden oak death (SOD), is caused by a fungus new to the United States, called Phytophthora ramorum. The fungus causes a bleeding necrosis on the trunks and limbs of affected oak and tanoak trees and can girdle and kill infected plant parts. The fungus also infects foliage, causing spots, blotches, or leaf tip necrosis of many kinds of plants without much notice or harm to the plants. Infected "carriers" of SOD may include rhododendrons, bay laurels, maples, viburnums, honeysuckles, buckeyes, and other trees and shrubs.
In Kentucky, our concern has been whether this disease would be similarly devastating to oaks if the pathogen were introduced into the state. The SOD disease fungus thrives in the relatively cool and moist climate of coastal California and Oregon. Because we also can have periods of cool, moist weather in spring and sometimes in fall, one might expect the disease to sometimes thrive here, too. The wide host range of the fungus includes Kentucky woody plants such as red oaks, rhododendrons, viburnums, and mountain laurels.
Effective February 14, 2002, a federal quarantine was imposed to prevent movement of infected plants or the pathogen from the West Coast to Kentucky and other states. However, the disease was known to be present in California for several years before the quarantine was imposed. During that time, it is possible that plants from California with P. ramorum were unknowingly shipped into Kentucky, possibly even through third-party commercial arrangements. Although such infected plants most likely have been sold and moved, the fungus could have escaped to vegetation surrounding the nursery or to younger plants in blocks that did not originate on the West Coast.
A survey of selected Kentucky nurseries was conducted to determine whether P. ramorum was present in nursery stock or in nearby vegetation. A spring survey was done during April, May, and June when the cooler weather would favor this disease. The survey was continued in September and October. Nurseries were examined for plants of all species showing abnormal symptoms including bleeding necrosis, leaf spots, blotches, and leaf tip necrosis. Nursery blocks containing oaks, rhododendrons, viburnums, and mountain laurels were especially scrutinized. Furthermore, in the woody vegetation in forest and fencerows surrounding the nurseries, plants with suspicious symptoms were also examined. The survey was further bolstered by collections of wild plants with suspicious symptoms made in Natural Bridge State Park and the Pine Mountain Settlement School. Collection locations are shown in Figure 1.
Figure 1. Sudden oak death survey locations.
Nursery and wild plant specimens were collected, placed in plastic bags, and immediately taken to the laboratory for analysis. Small pieces of infected plant material were plated on a culture medium selective for Phytophthora (PARP) and were floated on water in Petrie dishes. Samples were analyzed for growth and presence of the fungus Phytophthora. When Phytophthora was found, subcultures were grown on V-8 juice agar.
In spring, collections were made from eight nurseries and two natural areas in 10 counties. A total of 110 plant samples were collected for processing; 42 were from nursery blocks, and 68 were from nursery fencerows, adjacent forest edges, or natural park stands. Sampled plants included the following:
From nursery blocks: |
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4 or more samples each |
2 samples each |
1 sample each |
red maple (5), pin oak (5), red oak (8), rhododendron |
southern magnolia, sugar maple, white oak, viburnum |
white ash, river birch, bald cypress, American elm, ginkgo, hawthorn, hornbeam, dwarf English laurel, lilac, tree lilac, sweetbay magnolia, English oak, sweetgum |
From nursery fencerows, adjacent forest edges, and natural park stands: |
|||
4 or more samples each |
3 samples each |
2 samples each |
1 sample each |
American elm, sugar maple (6) |
American beech, hackberry, poison ivy, mountain laurel, red maple, white oak |
green ash, white ash, cat briar, American chestnut, box elder, honeysuckle, mountain laurel, chinquapin oak, red oak, sycamore |
blackberry, blueberry, flowering dogwood, gray dogwood, rough-leaf dogwood, slippery elm, American holly, bitternut hickory, shellbark hickory, black locust, mulberry, chestnut oak, persimmon, rhododendron, multiflora rose, sassafras, sumac, tulip poplar, Virginia creeper |
The plant specimens that were collected mostly had symptoms of spots, blotches, and leaf tip necrosis, but one white oak had symptoms of a bleeding canker, and a viburnum had a canker and shoot dieback. Although many plants had symptoms similar to those expected for plants infected with P. ramorum, Phytophthora was isolated from only one group of `Eskimo' viburnums. This unknown viburnum Phytophthora was examined microscopically for presence of sporangia, zoospores, oospores, and chlamydospores. The isolate appeared to differ morphologically from P. ramorum. This fungus will be analyzed using a polymerase chain reaction test to further identify the fungus and clarify any possible relationship to P. ramorum. This survey suggests that P. ramorum infected plants are absent or are not easily found associated with nurseries and native plant areas in Kentucky. Nevertheless, it will be important for nursery growers to continue surveillance activity in and near their nurseries on the off chance that this fungus has somehow found its way into Kentucky.
With increased national and international trade and movement of nursery stock, new plant diseases are always a threat to the Kentucky nursery and landscape industry. This survey suggests that P. ramorum, cause of Sudden Oak Death disease, is not present in Kentucky, which is good for the industry. If this disease were to be found here, disease eradication and quarantine measures would surely be imposed. These efforts, while necessary, can be costly to the nursery industry.
John Hartman and Edward Dixon, Department of Plant Pathology, and Margaret Mmbaga, Nursery Crops Research Station, Tennessee State University, McMinnville
Powdery mildew continues to be a problem in Kentucky landscapes (1). There are several effective fungicides available for use in nurseries and landscapes; there are also some promising resistant varieties becoming available as well.
This test was conducted at the University of Kentucky Horticultural Research Farm and was designed to test the reaction of dogwoods to powdery mildew caused by Microsphaera pulchra and Phyllactinia guttata. This site was one of several U.S. locations for these evaluations. Having a site in Kentucky was expected to increase exposure of the dogwoods to P. guttata, whereas dogwoods at other sites would be exposed primarily to M. pulchra. The dogwoods evaluated were selections made at the Nursery Crops Research Station, Tennessee State University, McMinnville, Tennessee. Three-year-old dogwood (Cornus florida) seedlings were grown in 3-gallon pots containing a nursery potting mix. Four plants of each selection were transported to Kentucky and were placed in a shade structure and watered as needed with automatic overhead sprinklers. Each of the selections was replicated four times, and plants were arranged in a completely randomized design. Dogwoods were evaluated for powdery mildew by recording percent powdery mildew incidence and severity on 10 June, 16 July, and 25 August. Incidence (percentage of the plant's leaves with mildew) was recorded based on presence of both signs of the pathogen and symptoms of the disease (with pathogen signs only visible with the aid of a hand lens). Severity is a measure of fungal activity and is based on the percentage of coverage of the infected foliage with visible signs of the fungus. Percent powdery mildew values were calculated by multiplying the percent incidence by the percent severity. The data were statistically analyzed using ANOVA and Waller-Duncan k-ratio t-test, (K = 100, P = 0.05).
Powdery mildew symptoms and signs were first observed in mid-June, and by mid-July disease pressure was heavy. By the end of the experiment, powdery mildew on the dogwood selections ranged from 19 to 77%. There were significant differences in powdery mildew levels between dogwood selections (Table 1). Under Kentucky conditions, selections R-14 and R-23 and M-18 and M-19 show promise as starting material for more resistant lines.
Table 1. Reactions of Tennessee dogwood selections to powdery mildew. |
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Selection number |
Percent powdery mildew* |
|||
|
10 June |
16 July |
25 August |
|
R-23 |
2.0 a ** |
16.5 a |
19.0 a |
|
M-19 |
11.0 abc |
15.0 a |
19.3 a |
|
R-14 |
3.3 a |
17.0 a |
28.8 a |
|
M-18 |
8.0 ab |
21.0 a |
28.0 a |
|
R-31 |
12.3 abc |
45.3 b |
49.0 b |
|
R-34 |
16.3 bc |
45.3 b |
51.5 b |
|
15 |
21.8 cd |
40.8 b |
44.0 b |
|
R-10 |
31.3 de |
49.3 b |
52.5 b |
|
R-25 |
35.8 e |
52.5 bc |
54.3 b |
|
R-9 |
40.3 ef |
67.8 cd |
defoliated |
|
R-33 |
51.5 f |
71.0 d |
77.0 c |
|
* |
Percent powdery mildew = % incidence (% of leaves with symptoms and signs of disease) x % severity (% average percent of leaf area with symptoms and signs of powdery mildew). |
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** |
In a column, means bearing the same letter are not significantly different (Waller-Duncan K-ratio test, P = 0.05). |
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With landscape industry concerns about the long-term health of flowering dogwoods during the current powdery mildew epidemic and consumer concerns about the use of fungicides in the landscape, there is a need to evaluate dogwood selections that are less prone to powdery mildew disease. Landscape managers, arborists, and nursery operators will have an interest in knowing if dogwood lines can be found to withstand powdery mildew in Kentucky.
1. Bachi, P.R., J.W. Beale, J.R. Hartman, D.E. Hershman, W.C. Nesmith, and P.C. Vincelli. 2004. Plant Diseases in Kentucky - Plant Disease Diagnostic Laboratory Summary, 2003. UK Department of Plant Pathology (in press).
Jennifer L. Flowers, John R. Hartman, and Lisa J. Vaillancourt, Department of Plant Pathology
Sphaeropsis tip blight (formerly known as Diplodia tip blight) is a common disease worldwide, affecting more than 30 species of pines and other conifers. Typical symptoms of S. sapinea infection include stunted shoots with necrotic, stunted needles, resinous cankers, and a general decline of the tree. These symptoms lead to significant economic losses of native and exotic pines in managed plantings. Latent infections of asymptomatic pine tissues by S. sapinea are common. A reliable DNA-mediated transformation protocol for S. sapinea would allow further study of the pathogenic and latent interaction between this fungus and its hosts. Successful genetic transformation of S. sapinea has not been previously reported (1).
The objective of this study was to develop a transformation protocol for S. sapinea. Protoplasts of S. sapinea (cells of the fungus without cell walls) were formed using a standard procedure for digesting cell walls and re-suspending the protoplasts. Protoplasts of S. sapinea were determined to be sensitive to the antibiotic hygromycin B. A bacterium, Agrobacterium tumefaciens containing the pBM2-2 plasmid, was used for transformation experiments. The pBM2-2 plasmid carries genetic information that confers hygromycin B antibiotic resistance. The bacterium was grown in liquid culture and mixed with a suspension of S. sapinea protoplasts. After co-cultivation with A. tumefaciens and incubation, the resulting S. sapinea was grown on a medium containing hygromycin B. S. sapinea colonies that grew in the presence of the antibiotic were single-spored and examined for morphological and genetic characters.
Isolates of S. sapinea that once were sensitive to hygromycin B were now resistant to the antibiotic due to the resistance genes obtained from A. tumefaciens. These are now transformed fungal isolates. They retained their normal colony types, spore morphology, and growth rates. Thus, S. sapinea transformants can be obtained with this Agrobacterium-mediated transformation protocol. The hygromycin-resistance gene integration into S. sapinea appears to be mitotically stable because repeated subculture of the fungus did not cause the fungus to lose its antibiotic resistance. This opens the way for integration of other genes into the chromosome of S. sapinea.
In future studies of this disease, it will be necessary to trace the progress of the fungus inside host pine trees. A genetically transformed version of S. sapinea can be created that will be easier to detect in the plant than the normal fungus. Knowing where the fungus is in the plant and whether it is in a latent or pathogenic state will enable studies on what environmental or plant factors might trigger the change from latency to pathogenicity. Identifying these events could help in devising tip blight disease control measures.
Amy Fulcher, Winston C. Dunwell, and Dwight Wolfe, Department of Horticulture
Rudbeckia taxa comprise a group of about 30 annual, biennial, and perennial plants, all native to North America (1). Rudbeckia are in the Asteraceae family and display the daisy-type disc and ray flower typical of that family. They range in height from 6 inches for the smaller pot varieties to 80 inches. Many Rudbeckia taxa, like R. hirta, tolerate dry conditions, while others, such as R. laciniata, prefer moist conditions (2). Rudbeckia are considered easy to grow and thrive in full sun. Rudbeckia can be distinguished from other similarly shaped flowers by their alternate leaves, yellow, rust, and/or orange ray flowers, and raised disc or "eye,"
Rudbeckia species and cultivars are valued native plants. In the last five years, landscape use of Rudbeckia fulgida var. sullivantii `Goldsturm' (1999 Perennial Plant of the Year) has become increasingly popular in residential and commercial landscapes. The focus of this study was to evaluate several less common Rudbeckia species and cultivars for landscape adaptability.
Four to eight plants of each taxa were planted at the University of Kentucky Research and Education Center in Princeton in the spring of 2002 and 2003. Preen® pre-emergent herbicide and Osmocote® 15-9-12, 5-6 month release fertilizer were applied and plants were mulched. Plants were fertilized with Miracle-Gro® 15-30-15 at 600 ppm nitrogen approximately weekly throughout the summer. The planting was irrigated at establishment, during liquid fertilizer applications, and during prolonged dry spells. The evaluation area was weeded as needed. Plants were not staked or sprayed for diseases or insects. The maintenance schedule was designed to simulate the conditions of an average home landscape.
Data were collected approximately once per week from early June through September on first bloom, bloom color, individual bloom size, and bloom coverage (percentage of the total plant covered by blooms). Bloom period (weeks in bloom), plant height, and plant width were also recorded. Observations were made on insect and disease incidence and cultural requirements.
General Summary 2002 and 2003
In 2002 R. fulgida var. sullivantii `Goldsturm' bloomed for the longest period of time, 10 weeks (Table 1). Rudbeckia fulgida `Green Wizard' did not bloom at all. In the second year of evaluation both R. fulgida var. sullivantii `Goldsturm' and Rubeckia triloba bloomed for more than 11 weeks.
Rudbeckia hirta `Autumn Colors', `Prairie Sun', `Goldilocks', and `Cherokee Sunset' had the greatest flower diameter in 2002. In 2003 Rudbeckia hirta `Cherokee Sunset' and `Autumn Colors' had the largest flower diameter.
Bloom coverage was not statistically significant either year. Some variation reported may be due to the subjective nature of percent coverage data (data were reported by different people in 2002 and in 2003).
Plant height ranged from Rudbeckia hirta `Toto Lemon' at slightly taller than 4 inches both years to Rudbeckia laciniata `Herbstsonne' at 55.5 inches in 2002 and 103 inches in 2003.
Plant width varied from one year to the next, and this is possibly more a reflection of a need to stake than an accurate reflection of the space required for each taxa.
Table 1. Results of the Rudbeckia taxa evaluation. |
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Cultivar |
Weeks in Bloom 2002 |
Weeks in Bloom 2003 |
Flower Diameter 2002 (inches) |
Flower Diameter 2003 |
Bloom Coverage 2002 |
Bloom Coverage 2003 (%) |
Plant Height (inches)1 |
Plant Width (inches)2 |
|
R. fulgida var. sullivantii ‘Goldsturm’ |
10.0 |
11.5 |
2.8 |
2.7 |
36 |
43 |
42.9 |
48.8 |
|
Rudbeckia hirta ‘Autumn Colors’ |
8.5 |
6.2 |
4.4 |
4.2 |
46 |
36 |
16.1 |
19.2 |
|
Rudbeckia hirta ‘Prairie Sun’ |
8.5 |
5.5 |
4.2 |
3.5 |
40 |
26 |
17.8 |
43 |
|
Rudbeckia subtomentosa |
8.0 |
6.3 |
3.3 |
2.8 |
41 |
14 |
64.7 |
76.8 |
|
Rudbeckia hirta ‘Cherokee Sunset’ |
7.5 |
8.0 |
3.9 |
4.4 |
46 |
40 |
26.3 |
39.9 |
|
Rudbeckia hirta ‘Sonora’ |
7.3 |
6.8 |
3.1 |
2.9 |
55 |
30 |
10.9 |
11.3 |
|
Rudbeckia hirta ‘Toto Gold’ |
6.7 |
6.0 |
2.6 |
2.3 |
41 |
43 |
8.0 |
8.8 |
|
Rudbeckia triloba |
6.0 |
11.6 |
1.3 |
1.4 |
62 |
24 |
52.2 |
38.2 |
|
Rudbeckia hirta ‘Toto Lemon’ |
5.7 |
6.5 |
1.9 |
1.7 |
31 |
31 |
4.0 |
7.1 |
|
Rudbeckia hirta ‘Toto Rustic’ |
5.3 |
7.3 |
2.1 |
2.3 |
38 |
26 |
7.8 |
6.5 |
|
Rudbeckia hirta ‘Goldilocks’ |
5.3 |
6.5 |
4.0 |
3.2 |
38 |
30 |
13 |
19.3 |
|
Rudbeckia laciniata ‘Herbstsonne’ |
1.3 |
6.8 |
3.4 |
3.0 |
42 |
13 |
103 |
57.8 |
|
Rudbeckia fulgida ‘Green Wizard’ |
– |
– |
– |
– |
– |
– |
– |
– |
|
LSD3 (P = 0.05) |
2.8 |
3.2 |
0.6 |
0.5 |
NS |
NS |
– |
– |
|
1 |
Average plant height including flower stalks taken July 28, 2003. |
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2 |
Average plant width including flower stalks taken July 28, 2003. |
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3 |
Least significant difference at the 0.05 probability level. |
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2002 and 2003
Rudbeckia hirta `Prairie Sun' began the season with butter yellow outer portions of the ray flowers and darker, golden yellow interior portions of the ray flowers. The disc flowers began as a yellow-chartreuse color. As the season progressed and seeds developed, the disc color changed to brown, altering the aesthetic qualities of the flower. Rudbeckia hirta `Autumn Colors' displayed variable flower color ranging from yellow to dark orange to rust colored ray flowers. Flowering was variable in 2002 on Rudbeckia laciniata `Herbstsonne' with just two of the four plants developing flower stalks and flowers. All four plants bloomed their second year. In the 2002 study R. fulgida var. sullivantii `Goldsturm' did not have one of the highest bloom coverages, but an established planting nearby began blooming earlier and bloomed as late into the season and appeared to have greater bloom coverage than the first-year plants in the evaluation. Data from 2003 show that a more established R. fulgida var. sullivantii `Goldsturm' does bloom for a longer period of time.
2002
Shining flower beetles were identified on Rudbeckia hirta `Cherokee Sunset' but did not cause damage. Japanese beetles, spittle bugs, caterpillars, and cucumber beetles were noted on occasion but did not appear to cause any noticeable damage. Rudbeckia triloba was the exception, sustaining noticeable, yet minor damage from Japanese beetles. Soldier beetles, a beneficial insect, were identified in large numbers on the flowers of several varieties.
In July several taxa began to display disease symptoms. On July 22 Rudbeckia fulgida `Green Wizard' and Rudbeckia hirta `Goldilocks' were diagnosed with rhizoctonia root and stem rot. All of the Rudbeckia hirta `Goldilocks' and half of the Rudbeckia fulgida `Green Wizard' died. As the season progressed, the R. hirta Toto series and R. hirta `Sonora' also succumbed to rhizoctonia. By the end of September plants of Rudbeckia hirta `Autumn Colors', `Cherokee Sunset', and `Prairie Sun' had also died. Powdery mildew was noted on Rudbeckia hirta `Autumn Colors' and Rudbeckia hirta `Cherokee Sunset' in late August. Rudbeckia fulgida var. sullivantii `Goldsturm' was diagnosed with cercospora leaf spot in October, after several rain events. The symptoms associated with the cercospora were also present in April and May during a period of wet weather.
2003
In early July leaves and stems of one Rudbeckia subtomentosa plant began to die. Sclerotinina sclerotiorum, the causal organism of sclerotinina stem rot, was identified as the cause. No other Rudbeckia subtomentosa died. Later in July Rudbeckia hirta `Goldilocks' was diagnosed with southern blight, Sclerotium rolfsii. All four plants died. In August Rudbeckia fulgida var. sullivantii `Goldsturm' was diagnosed with cercospora leaf spot. The leaf spot did not detract from the overall aesthetic impact of the plants. Also in August Rudbeckia hirta `Cherokee Sunset' and Rudbeckia triloba were diagnosed with a root and stem rot associated with rhizoctonia. None of the R. triloba died, but three out of four R. hirta `Cherokee Sunset' died. During August and September nearly all plants of Rudbeckia hirta `Toto Gold', Rudbeckia hirta `Toto Rustic', Rudbeckia hirta `Toto Lemon', Rudbeckia hirta `Sonora', Rudbeckia hirta `Autumn Colors', and Rudbeckia hirta `Prairie Sun' succumbed to rhizoctonia stem and root rot. Leaves on the lower portion of Rudbeckia laciniata `Herbstsonne' stalks turned brown and clung to the stem. No cause was determined.
Nearly all plants had holes in the leaves indicating feeding from a chewing-type insect, but no insects were found. Snout weevils were noticed in large numbers in late May feeding on the flower buds of Rudbeckia fulgida var. sullivantii `Goldsturm'. This infestation was short-lived and did not result in any noticeable damage. Japanese beetles were present individually on R. triloba but did not cause noticeable damage.
2002
Rudbeckia laciniata `Herbstsonne', Rudbeckia subtomentosa, and Rudbeckia triloba needed to be staked, possibly due to the high rate of nitrogen applied in the liquid fertilizer. In September R. triloba and R. subtomentosa exhibited symptoms consistent with ozone damage.
2003
While some plants of Rudbeckia laciniata `Herbstsonne', Rudbeckia subtomentosa, and Rudbeckia triloba needed to be staked, other plants did not.
No plant in the study was free from problems. However, during the period of evaluation, some taxa were able to survive and flower during dry periods as well as periods of wet weather and high temperatures, while others died. Based on the number of plants dying from rhizoctonia, annual Rudbeckia hirta cultivars may be more susceptible to rhizoctonia than the perennial Rudbeckia taxa. Considering that rhizoctonia is generally considered to be ubiquitous, growers, retailers, and landscapers may wish to use these plants in clean containers filled with a sterile medium.
Barring a progression of the symptoms seen on the lower leaves in 2003, Rudbeckia laciniata `Herbstsonne' is a good choice for areas requiring a tall plant. It may require staking. Preliminary observations show it may make a nice cut flower due to a long vase life.
At this time Rudbeckia fulgida var. sullivantii `Goldsturm' continues to be a reliable bloomer and free from significant pest problems.
Rudbeckia subtomentosa and Rudbeckia triloba show promise as relatively trouble-free perennials, R. subtomentosa for midsummer bloom and R. triloba for season-long bloom. Their apparent ability to withstand disease pressure without significant plant death may lead to preferred use over R. hirta cultivars.
Identification of adaptable, attractive, native plants can provide landscape contractors, designers, and retailers with an expanded list of plants to market to the consumer as well as a wider selection of low maintenance plants for commercial landscapes. In addition, this evaluation will serve as a basis for modeling future evaluations of Kentucky native Rudbeckia stands for landscape use.
The authors would like to recognize June Johnston, Hilda Rogers, and Julie Miller for their contributions to the Rudbeckia taxa Evaluation. The authors would also like to thank Dr. Robert Anderson for his assistance. Appreciation is expressed to the Kentucky Horticulture Council, the UK
