Influence of timing and prey availability on fruit damage to apple by Campylomma verbasci (Hemiptera: Miridae).

Campylomma verbasci Meyer is a zoophytophagous mirid that feeds on small arthropods as well as apple (Malus domestica Borkhausen) fruits, causing economic damage to some cultivars. The influence of timing and prey availability on the amount of fruit damage was studied to determine whether either factor could be used to refine a management program. C. verbasci nymphs were caged on branches of fruiting 'Golden Delicious' apple trees during the period from bloom through early fruit set. The greatest amount of fruit damage occurred during the bloom period; little or no damage occurred after fruit reached approximately equals 13 mm in diameter. The availability of prey did not reduce the incidence of fruit damage by C. verbasci, nor did it influence the survival of nymphs. Nymphal survival was higher, however, in cages where a blossom or fruitlet was present versus a vegetative spur. These data support the hypothesis that post petal fall insecticide applications (those made after the fruit is greater than approximately equals 10-13 mm in diameter) are not useful in preventing economic levels of fruit damage in Washington State, and that petal fall applications would only prevent a fraction of the total amount of damage by this pest. The data from this study do not support the hypothesis that manipulating arthropod prey species of C. verbasci will prevent fruit damage. There was evidence to support the hypothesis that nymphs can survive a relatively short period (7 d) without arthropod prey.