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. The threshold for treatment is three percent or more of the total plants infected with aphids, or if there are six or more aphids per 100 sweeps. Treatment by air is generally not effective against aphids. Feeding by aphids can cause leaves to curl and the aphids themselves can be a source of contamination after heading.
Treatment is recommended if there is more than five aphids per plant.
Heavy rains are a major source of mortality to aphids, so fields should be re-scouted after such rains, to make sure treatment is warranted. The relative low numbers of moths caught in pheromone traps indicate that the summer moth population is low this year. However, there are still corn borer moths out there laying eggs. Sweet corn with ears, peppers, and snap beans with fruit should be treated preventatively, especially if the tolerance for damage and contamination is low. Mites Mites are reported in beans and tomatoes.