The Mite Searching Ability of Stethorus punctum1 within an Apple Orchard 23

The ability of the predator Stethorus punctum (LeConte) to find the European red mite, Panonychus ulmi (Koch) within an apple orchard was investigated in a 1-ha block. In the 148-tree orchard, only 8 trees were selected on which to allow an increase in the mite populations; the remaining trees were kept free of mites by applying acaricide sprays when deemed necessary. S. punctum adults demonstrated the ability to find the mites on the 8 trees when the mite population averaged less than one mite/leaf among the 8 trees. The adult females began depositing eggs on mite infested leaves when the population ranged from 1–2 mites/leaf. The results of this experiment possibly indicate that S. punctum may use some stimulus other than random searching to find mites in apple orchards.