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Biology and Management of Insects Attacking Turf and Woody Landscape Plants
D.A. Potter, C.T. Redmond
Department of Entomology
More than 80% of US citizens reside in cities and suburbs, creating high demand for lawns, gardens, trees and shrubs, parks, golf courses, playing fields, and other green spaces. As natural areas and croplands give way to suburbs, stable communities of native plants and animals are supplanted by relatively low species diversity of street trees and manicured turf, and a mosaic of ornamental plants, all frequently maintained with fertilizers, water, and pesticides.
Often such changes are associated with higher densities of insects that rarely, if ever, reach become pests in natural forests or grasslands. Ever-tighter restrictions on insecticides and invasion and range expansion of serious alien pests (e.g., emerald ash borer) highlight the need for safe, effective solutions to pest problems of lawns, landscapes, sport fields, golf courses, parks, horse farms, and production nurseries and sod farms. Urban plantings also supply oxygen, filter dust, reduce glare, soil erosion, water runoff, and noise pollution, and reduce street temperatures, and they enhance recreational and leisure activities, making cities and suburbs nicer places to live and work. These benefits are critical to mental and physical well-being of urban citizens.
Turf culture alone is a >$45 billion per year industry in the USA. There are > 600 million urban trees in the USA having immeasurable value. Horticulture, including nursery, greenhouse, floriculture, and sod, is a multi-billion dollar per year industry. It is especially important in Kentucky's agricultural transition from tobacco.
My research program has studied insect pests of turf and landscapes for 31 years. It has provided safe and effective solutions to pest problems for homeowners and professional landscape managers, and supported environmental stewardship by the horticultural industries. We have trained many students now working as professional entomologists. A focus of the proposed work is to support a transition from control that relies on broadly toxic insecticides to an approach that incorporates conservation biological controll, resistant trees, shrubs, and grasses and, as necessary, reduced-risk insecticides. Its breadth reflects the diversity of urban pest problems and interests of present and future student investigators.
2011 Project Description
Compatibility with pollinator conservation was compared among different classes of lawn insecticides, including a new anthranilic diamide that may have little or no impact. Bees and other pollinators visiting flowering weeds in suburban lawns were surveyed for biodiversity and what types may be at risk of exposure. Biodiversity of beneficial insects was surveyed in golf course naturalized areas, and in high or low-mowed turf plots, and sentinel prey (pest insects) were exposed in, and at varying distances from such areas to assess their contribution to biological control. Replicated wildflower plots with KY-adapted blends of flowers designed to attract bees, butterflies, and other pollinators were established on six golf courses for biodiversity surveys to be conducted in 2012-2013.
A saponin-rich organic by-product of tea oil manufacture was evaluated for mitigation of earthworm casts, a worldwide problem on closely mowed turf playing surfaces, and studies to determine the species responsible for casting and their seasonal biology were initiated.
Flowering perennials were screened for attracting beneficial wasps that parasitize lawn grubs, and continued evaluations of 20 species or cultivars of Dutch-elm disease-resistant elms in the National Elm Trial provided new information on the trees' relative resistance to scale insects, weevils, and other pests.
Trials showed that increased use of "livestock-friendly" improved tall fescue forages having soft texture or lacking ergot alkaloids is unlikely to aggravate insect injury to pastures. Studies of tri-trophic effects of endophytic lawn grasses on parasitoids having different life histories provided insight on how host plant resistance can be integrated with biological control.
Members of my lab presented 40 outreach talks to thousands of attendees at the KY Turfgrass Council, KY Landscape & Nursery Association, and Central KY Ornamental and Turf Association's Annual Conferences, Winter Workshops, and/or Summer Field Days, Lexington Children's Emporium, and at out-of state conferences.
Our lab is influential in supporting environmental pest management for urban landscapes in the US and worldwide. Our research is published in high impact journals and presented at major scientific conferences, but we also publish in trade magazines and speak at venues for non-scientists (school children, educators, landscape practitioners) who can learn from and use our findings. The PI, for example, has been invited to present the Keynote Address for Pest Management at the 2013 International Turfgrass Conference (in Beijing), and in 2011 coauthored (with a former UK grad student) the first Annual Review article (top Impact Factor among Entomology journals) on turf insects in >20 years.
Our research on earthworm cast mitigation, published first in an international peer-reviewed journal, was also featured in US trade journals and subsequently reprinted in magazines in Germany, Spain, and New Zealand. The botanical product was deemed intellectual property by UK, leading to a commercial agreement with a company that began paying royalties to the University in 2011.
Our work in conservation biological control and pollinator conservation is influential - it is the first to survey bees on urban lawns, first to assess risks of modern urban landscape insecticides to bees and other beneficial insects using realistic exposures, first to assess the ecosystem services provided by established naturalized areas in turf settings, and first to establish bee conservation research plots on US golf courses.
Another of our projects provided assurance that pasture grasses being developed by UK scientists and the USDA Forage-Animal Production Research Unit (FAPRU) for improved livestock performance will not aggravate pasture insect outbreaks, and our black cutworm studies provide insights on integrating microbial and biological control with pest-resistant endophytic grasses. In 2011 we published high-impact refereed journals, trade magazines, and extension bulletins, had three book chapters accepted for publication in 2012. We presented talks to thousands of scientists and end-users.
Redmond, C.T., Potter, D.A. (2010). Incidence of turf-damaging white grubs (Coleoptera: Scarabaeidae) and associated pathogens and parasitoids on Kentucky golf courses. Environ. Entomol. 39:1838-1847.
Keathley C.P, Potter, D.A. (2010). Does modification of tall fescue leaf texture and forage nutritive value for improved livestock performance increase suitability for a grass-feeding caterpillar Crop Sci. 51:370-380.
Vanek, S.J., Potter, D.A. (2010). Ant-exclusion to promote biological control of soft scales (Hemiptera: Coccidae) on woody landscape plants. Environmental Entomology 39:1829-1837
Keathley, C.P., Potter, D.A. (2011). Behavioral plasticity of a grass-feeding caterpillar in response to spiny- or smooth-edged leaf blades. Arthropod-Plant Interactions 5: 339-349.
Keathley, C.P., Potter, D.A. (2011). Arthropod abundance in tall fescue, Lolium arundinaceum, pastures containing novel safe endophytes. J. Appl. Entomol. DOI: 10.1111/j.1439-0418.2011.01698
Bixby-Brosi, A.J.., Potter, D.A. (2011). Can a chitin synthesis inhibiting turfgrass fungicide enhance black cutworm susceptibility to a baculovirus Pest Manag. Sci. DOI 10.1002/ps.2252
Bixby-Brosi, A.J., Potter, D.A. (2011). Parasitoid life history strategy influences endophyte mediated tritrophic interactions with a grass-feeding caterpillar. Arthropod-Plant Interactions. DOI 10.1007/s11829-011-9163-2
Larson, J.L., Redmond, C.T., Potter, D.A. (2011). Comparative impact of an anthranilic diamide and other insecticidal chemistries on beneficial invertebrates and ecosystem services in turfgrass. Pest Manag, Sci. DOI 10.1002/ps.2321
Potter, D.A., Redmond, C.T., and Williams, D.W. 2011. The worm turns: earthworm cast reduction on golf courses. Golf Course Management, Sept. 2011, pp. 86-96.
Potter, D.A., Redmond, C.T., and Williams, D.W. 2011. Controlling earthworm casts on golf courses. U.S. Golf Assoc. Green Section Record 49: 1-4.
Hartman, J., Dixon, E., Potter, D.A., Hart, J., Fountain W. National elm trial-Kentucky data, 2010. UK Nursery/Landscape Program Research Report. UK-PR 602, p. 24-25.