Biology of Orius insidiosus (Heteroptera: Anthocoridae): A Predator in Virginia Apple Orchards

Egg and nymphal development of Orius insidiosus</it> (Say) was studied at 17, 23, 29, and 35°C. There was a linear relationship between development rate (1/days) of O. insidiosus</it> and temperature. Developmental threshold temperatures were calculated as 10.2°C for eggs and 8.9, 7.5, 10.7, 12.4, and 9.9°C for instars 1–5, respectively. A 10.0°C developmental threshold was determined for total nymphal development. Mean degree-day requirements for development were calculated for all stages studied. Laboratory and field observations established that a number of small, soft-bodied insects and mites as well as the eggs of several Lepidoptera are acceptable as prey. O. insidiosus</it> also fed on other beneficial species including predaceous thrips and mites. A number of general orchard predators, particularly spiders, chrysopids, and other predaceous Heteroptera, were found to prey upon O. insidiosus</it>. Numerous weeds and crops serve as alternate sites for O. insidiosus</it> populations. Corn and alfalfa adjacent to apple orchards in Virginia apparently serve as a reservoir for O. insidiosus</it> throughout the season. Thistles (Carduus</it> spp.) harbor large numbers of O. insidiosus</it>, which prey on thrips. These natural and cultivated alternate sites may be important to management of O. insidiosus</it> populations.