The effect of a nucleopolyhedrovirus (CrSNPV) infection on larval growth and feeding activity of the obliquebanded leafroller, Choristoneura rosaceana (Harris) was studied at 23°C and under a photoperiod of 16L:8D. Neonates (L1) or third instars (L3) were treated with 0 (i.e. control) or 3.3 x 108 PIB ml-1 of CrSNPV. Larval development until pupation or death was delayed by 6 to 12 days when individuals were infected as neonates. Diseased larvae experienced a 93.9% mortality, mostly during the first (39.6%), fifth (14.3%) or sixth (29.7%) instars. For individuals that completed 5 or 6 instars before they died, delays in larval development were observed in the first instar (ca. 6 days) and for following instars (ca. 1 to 2 days) When larvae were treated as L3, no difference in larval duration was observed between survivors of the control and CrSNPV treatments. Diseased larvae (85.5% of treated larvae) reached the fifth (41.5%) or the sixth (44.6%) instars before they died. The larval period of individuals that completed 5 or 6 instars before death was prolonged by 1 to 3 days during the two last instars. In both L1 and L3 treatments, the total amount of food consumed during the entire larval period by survivors of virus infection was similar to non-infected individuals. Feeding rate (in a 6h period) during the last instar in which larvae died was reduced by about 45-52% and 25-37% after treatment of respectively neonate or third instars. With prolonged larval development, a significant reduction of food consumed was observed only after treatment as neonate larvae.
Species 1: Lepidoptera Tortricidae Choristoneura rosaceana (obliquebanded leafroller)
Keywords: Virus, Feeding activity
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA