Habrobracon gelechiae Ashmead (Hymenoptera: Braconidae) was studied as a parasitoid of the obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae) in California pistachio (Pistacia vera L.) orchards. Ovipositional behavior, adult longevity and fecundity, and the effects of temperature on developmental time and survival were determined. Habrobracon gelechiae develops as a gregarious, ectoparasitic idiobiont on late-instar C. rosaceana larvae. At 25°C, adult female wasps survived longer when provided honey and water (35.4 ± 4.9 d) or honey, water, and host larvae (34.4 ± 2.4 d) than when provided water (8.9 ± 1.1 d) or no food (5.9 ± 0.8 d). Over the adult lifespan, females parasitized 20.6 ± 2.1 hosts and deposited 228.8 ± 24.6 eggs. The intrinsic rate of increase was 0.24, the mean generation time was 18.15 d, and the double time 2.88 d. At constant temperatures, H. gelechiae successfully developed (egg to adult) from 15 to 35 °C. The developmental rate was fit to a nonlinear model, providing estimates of the parasitoid's lower (10.5 °C), upper (36.0 °C), and optimal (33.3 °C) development temperatures. Based on a linear model, 155 degree days were estimated for egg to adult eclosion. Temperature-dependent nonlinear model of survival showed similar shape with the model of development rate. The wasp developed under two diurnal temperature regimes, with 31.0 ± 13.3% survival at low (4-15 °C) and 63.0 ± 11.4% survival at high (15-35 °C) temperature regimes. The results are discussed with respect to H. gelechiae potential as a parasitoid of C. rosaceana in California's San Joaquin Valley.

TitleAbstract Grapevine leafroll-associated virus 3 (GLRaV-3) is associated with the economically damaging grapevine leafroll disease, and is transmitted in a semi-persistent manner by several mealybug species. We performed the first controlled field study of vectormediated inoculations with GLRaV-3 in a commercial vineyard with previously asymptomatic vines, and monitored the vines during four growing seasons. We then compared the outcome of vector-mediated inoculations in the field study to an analogous laboratory study. In the vineyard, about half of all inoculated plants became infected with GLRaV-3, fewer than in the controlled laboratory inoculations. Mealybugs had lower settling and feeding success in the field than in the laboratory inoculations. Our study suggests that laboratory studies may overestimate transmission efficiency. All successfully inoculated vineyard plants first became symptomatic one growing season after inoculations, and berry quality declined within one year after inoculations. Vineyard plants were effective virus sources one year after inoculations. Our findings generally indicate that newly symptomatic vines in commercial vineyards probably became infected during the previous growing season, and a decline in berry quality can be expected during the same year in which symptoms appear.