Lethal And Sublethal Effects Of LdNPV Geographical Strains On Asian Gypsy Moth

Gypsy moth, Lymautria dispar L., is one of the most important Lepidopteron defoliafor pest over the world. Gypsy moth has different geographic strains, such as European strain and Asian strain, for its wild distribution region. It is a good way to use its Nuclear polyhedrosis virus (LdNPV) to control gypsy moth, but it is not clear that if the different geographical strains of LdNPV have different violence to Asian gypsy moth. So it is very important to study lethal and sublethal effects of different geographical strains of LdNPV on Asian gypsy moth. Lethal and sublethal effects of different strains of LdNPV on Asian gypsy moth were studied under the laboratory condition. Asian gypsy moth larvae were fed by artificial food in the automatic climate chest (L:D=16:8, T=25±1℃, RH=60±10%). Three geographic strains of LdNPV were used. A contaminated diet-plug method was used to determine the dose-response and time-response of Asian strains of gypsy moth larvae to each NPV strains. LC50 of LdNPV-D, LdNPV-H and LdNPV-J is 1.33×102 OBs/μl ,1.68×103 OBs/μl ,4.66×103 OBs/μl respectively. The slope for LdNPV-D, LdNPV-H, LdNPV-J is 1.302±0.0772, 1.5934±0.0898, 1.0132±0.0574 respectively. LC90 is 1.28×103 OBs/μl , 1.07×104 OBs /μl , 8.58×103 OBs /μl respectively. LT50 is 9.06d,9.95d,7.78d respectively. LT90 is 11.35d,12.33d,9.10d respectively. LdNPV-D strain has more violent lethal effect on gypsy moth than the others. Sublethal LdNPV concentrations were used to treat the second instar larvae of Asian gypsy moth to determine the sublethal effects of LdNPV strains on gypsy moth. The effect on gypsy moth larvae development duration is significant. Male and female larvae stage was short than that of control. Male and female pupil stage was longer than that of control. Pupal duration was prolonged. There was no influence on female and male adult life stage. LdNPV treated female pupal was weightier than that of control. LdNPV treated male pupal was lighter than that of control. LdNPV treated female lay more eggs than that of control. The difference of sublethal effects on gypsy moth between the three strains was not significance.