Potato leafhopper is present on maple trees in Kentucky. Be watchful for this insect, particularly on red maples, in southern Illinois. Typically, potato leafhoppers appear in large numbers in alfalfa before they move to landscape plants. Control these insects with any of the labeled pyrethroid insecticides such as bifenthrin (Talstar), cyfluthrin (Tempo), lambda-cyhalothrin (Scimitar), or permethrin (Astro, Pounce, Ambush). Pounce and Ambush can only be used in nurseries.
Euonymous scale crawlers are also present in Kentucky and should be showing up in southern Illinois. They can be controlled with a variety of insecticides while they are in this vulnerable crawler stage.
Pine needle scale crawlers have hatched on white pine in northeastern Illinois. The adults, visible all year round, look like white flecks and are teardrop shaped. In a heavy infestation, a tree can look almost flocked white. The tiny red crawlers are controlled with a variety of insecticides listed in the Illinois Commercial Landscape and Turfgrass Pest Management Handbook, 1998–1999.
Euonymus webworm (also known as Euonymus caterpillars) has been found on running strawberry bush (Euonymus obovatus) in northeastern Illinois. This insect was present in large numbers last year in this part of the state, particularly on European euonymous. Look for larvae in small webs. The webs increase in size as the larvae feed on the leaves and can become large. The slender caterpillars are a very pale yellow with black spots and can grow up to 4 or 5 inches long. Bacillus thuringiensis var. kurstaki (Bt) will control young larvae but is less effective on mature larvae. Penetrate the web thoroughly with Bt as the insect must eat the Bt in order for it to work. Other insecticides are also effective.