The potential of three native insect predators to control the rosy apple aphid, Dysaphis plantaginea

摘要: The potential of three aphidophagous predators, Adalia bipunctata, Aphidoletes aphidimyza, and Episyrphus balteatus to control the rosy apple aphid, Dysaphis plantaginea Pass., a major pest on in Europe, was assessed by means laboratory field cage experiments Northern Switzerland. Under conditions, all predators efficiently preyed upon D. seedlings. searching success larvae A. bipunctata for individual aphids not dependent size branches trees varying leaf surface area from 150 cm2 960 cm2. Fifty 70% were found killed 6 hours 48 hours, respectively, after release single second instar larva bipunctata. In first experiment 1996, lesser extent E. balteatus, proved be effective consistent during spring being little affected cool temperatures wet weather. subsequent 1997, released singly combination aphid infested seedlings study interactions between these two promising agents. Both species had significant negative effect population increase. did significantly interact thus, their joint is best explained an additive model. Combined releases predator reduced densities 5% control. This indicates augmentative native plantaginea.