Bio-efficacy of Entomopathogenic Nematodes against Serpentine Leafminer (Liriomyza trifolii Burgess) in Oilseed Crops

Abstract

Serpentine leaf miner is a polyphagus pest native to United States of America, and the caribbean. It was introduced into India in 1990’s along with cut chrysanthemums and it was first reported in annual castor group meeting held at Hyderabad. It has very wide host range with 78 annual plant species as host. Damage is mainly caused by larva as it mines below the leaf epidermis causing damage to the leaf mesophyll. Adult flies punctures the leaf tissue both for feeding and oviposition causing stripling appearance on leaves. The mines caused by the larva even act entry points for pathogens making the plant susceptible to secondary infection. Several natural enemies like predators, parasitoids and pathogens control leaf miner populations in the field. Most of these natural enemies get killed due to chemicals applied during the season to control other pests. Entomopathogenic nematodes are one of the most virulent pathogens killing different life stages of the insect pests. An Entomopathogenic nematode, Heterorhabditis bacteriphora was tested against late instar larvae and pupa of Liriomyza trifolii. Infective juveniles (ijs) were inoculated @ 50 ijs per larvae/pupa. About 50% mortality was observed in late instar larvae in 24 hours post infection. Pupae were not infected by this nematode and 100% adult emergence was observed. This bioassay demonstrates that EPNs have potential for biocontrol of Liriomyza trifoli in oilseed crops. The bioassay will be repeated with different doses of H.bacteriophora for reconfirmation of results.