Pathogenicity of new isolates of entomopathogenic nematodes on major insect pests of Western Ghats in South India.

摘要

Studies were conducted on the pathogenicity and multiplication of Steinernema carpocapsae, S. riobrave, S. siamkayai, S. asiaticum and Heterorhabditis indica on four important lepidoterous insect pests of forest trees in South India. The four insect pests tested were: Sahydrasus malabaricus, Indarbela quadrinotata, Hypsipyla robusta and Hyblea puera. The percentage of insect mortality and production of infective juveniles (IJ) in the host insect larvae were directly proportional to nematode inoculum density. The percentage of mortality was found to be maximum at 100 IJ inoculum densities in all four host insect pests. S. carpocapsae caused the maximum percent mortality of I. quadrinotata larvae (91.6) while the maximum infective juvenile production per larva was observed in S. malabaricus (5.1) at the inoculum level of 100 IJ/larva. The mean infective juvenile production per larva in S. malabaricus, I. quadrinotata, H. robusta and H. puera was 5.1, 4.7, 4.1 and 3.8, respectively. Among the four insect pests tested, S. riobrave caused maximum percentage mortality of H. robusta (79.6) followed by S. malabaricus (76.6). The IJ production per larva of S. malabaricus, I. quadrinotata, H. robusta and H. puera was 0 to 5.18, 3.42 to 5.18, 3.42 to 4.32 and 0 to 4.99, respectively. The maximum number of IJ was produced in S. malabaricus (4.95) at the 100 nematode inoculum level.