If populations are high, insecticide application may be to prevent disease transmission in susceptible crops, and to limit damage to fruit caused by the beetles' feeding. The need to control cucumber beetles with insecticides must be balanced with the need to protect bees, which are essential for pollination of cucumbers, squash, and melons. It is best to take care of cucumber beetle problems before bees are in the field. If insecticide applications are necessary after flowering, apply insecticides when flowers are closed and bees are not working the field. In general, dust formulations are very toxic to bees.
Wettable powders are also toxic to bees.
Aphids Aphids are reported on celery and cabbage. During the hot, dry days of summer aphid populations can build rapidly. Pyrethroids, which are used to control other insects, such as loopers and cutworm in celery, can facilitate the increase of aphids by killing their natural enemies. The use of fungicides to prevent disease can also increase aphids by killing the fungi that attack and kill aphids. Celery growers should scout their fields frequently for aphids, especially during hot, dry weather.