Issue 14, August 14, 2009
Scouting Watch
Magnolia scale is also being found in high numbers in central Illinois. Infestations have been reported from Peoria, Springfield, and Urbana. There are adult female scales in Urbana with no sign of egg production yet. This corresponds with crawler production expected in late September.
In the last issue, only crawler control recommendations were given because imidacloprid or other systemic insecticide applications would be unlikely to provide control this late in the season. Even trunk injections this late in the season on a twig and trunk feeding pest might not build up to effective levels until after egg-laying has occurred. However, soil drench or microinjection of imidacloprid (Merit, Imicide, Xytect, Pointer) will provide control for at least one year. Application at this time of year should provide control next spring when the crawlers settle down to feed.
White Grubs had not been found in central Illinois nor reported from elsewhere in the state as of August 14. Scouting on August 13 in a couple of locations in Urbana did not reveal any hatched grubs. It is assumed that the grubs have hatched, but may be too few in number to be discovered during limited sampling.--Phil Nixon
Author:
Phil Nixon