Insects:
Borers
It is never too early to plan borer control. Consult the IPM Calendar for Deciduous Tree Production or U.K. publication ENT- 43 Insect Borers of Trees and Shrubs. Traps and phenology charts such as Timing Control Actions for Landscape Insect Pests Using Flowering Plants as Indicators can be used for all borers and many other insects. One of the first borers to emerge is the lilac borer (late April).

Chlorpyrifos Pro 4 and Dursban TNP (EC formulations of chlorpyrifos) are labeled for borer control in nurseries. Some entomologists feel these products will not be available much longer. Dr. Dave Shetlar, OSU, reported at the BMP Workshop that permethrin products as EC formulations have the best sticking power for borer control. They are adsorbed onto the bark and do not wash off easily like wettable powder and flowable formulations. As patents run out secondary formulators/distributors begin selling these products; be sure to check if a secondary product is the EC formulation. Dr. Christine Casey, reported at the NCSU Nursery Shortcourse that the systemic imidacloprid is an effective flatheaded appletree borer control if applied early enough to be taken up by the plant.

Maple Mites
Oligonychus aceris, the maple mite has been identified as the likely culprit of mite damage noticed on maples, primarily on Autumn Blaze® last season. The stipling damage, along with cercospora leaf spot, interfered with fall color. Growers can scout with a hand lens for eggs. Most eggs have been observed on branches slightly larger than pencil size on the rough area just under a bud. Dormant oil can be used very effectively to control mites overwintering on the plant. In contrast, twospotted spider mites overwinter in grassy and weedy growth off of the plant, therefore dormant oil is not effective at controlling them. Container growers may want to control maple mites in order to maximize fall color.

Oils, soaps, and water are the few things to which mites have not developed resistance. Dormant oil can be applied when the temperature is in the 40's as long as the temperature doesn't drop to below freezing, or at least doesn't freeze before the oil dries.

Source: Johnson and Lyon. Insects that Feed on Trees and Shrubs. Cornell University Press. 2nd edition.
Thanks to Rayanne Lehman, Pennsylvania Department of Agriculture & David Shetlar, Ohio State University.

Weeds:
Don't forget to apply a preemergence herbicide in order to reduce weed problems later in the season. Growers who did not apply a preemergence herbicide last fall should be especially dilligent about applying a herbicide soon, before the majority of germination takes place. Some preemergence herbicides have postemergence activity: Goal, Atrazine, Casoron, Princep,and Kerb. (Atrazine is currently only labeled for conifers.) Kerb even provides postemergence control of perennial grasses but is best applied in late fall.

Goal can effectively control small weeds up to 4" in height. The Goal label has been expanded to include a limited number of deciduous trees. Some species on the label include green and white ash, river birch, cherry, crabapple, dogwood, lilac, red maple, sugar maple, several oaks, plum, redbud, sweetgum, sycamore, and black walnut. For best control clean cultivate the soil prior to application. Goal requires sunlight to be active; do not mulch after applying Goal. Disturbing the soil after application may reduce herbicidal effectiveness.

Source: Controlling Weeds in Nursery and Landscape Plantings. Penn State Pub. UJ236.

When a pesticide drifts and damages a crop economic loss can occur. Ken Franks, Branch Manager of the Kentucky Department of Agriculture, Division of Environmental Services (formerly the Division of Pesticide Regulation), recently gave a synopsis of the Kentucky pesticide laws as they relate to drift onto nursery crops:

The applicator is responsible for applying the pesticide according to the label. All labels have some statement related to the prevention of drift. If damage occurs to a nursery crop, contact the Division of Environmental Services and make an official complaint: 1 (866) 289-0001. They will conduct an investigation of the complaint. If they determine that the product used drifted onto a neighboring nursery crop it would be possible for the nursery grower to collect damages.