Assessment of entomopathogenic nematodes in agrotis ipsilon (Lepidoptera: Noctuidae) under laboratory and greenhouse conditions

Abstract

This work aims to evaluate the potential of Brazilian isolates of entomopathogenic nematodes through the selection of isolates for Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae). In order to analyze the susceptibility at different instars of the insect and different concentrations, to investigate the in vivo production of these isolates, and to perform greenhouse tests in the Laboratory of Entomologia e Controle Microbiano of Universidade Estadual do Norte do Paraná, Brazil. Selection tests were carried out with nine isolates, and those that caused greater percentages of insect mortality were used in concentration tests (0, 50, 100, 150, 200 Infective Juveniles (IJs)/cm2), with different instars of the insect (2nd, 3rd, 4th, 5th, 6th instars and pupa), in the in vivo production of A. ipsilon larvae, and in pathogenicity tests in a greenhouse. In the selection test, the isolate CH3 (Steinernema sp.) caused 100 % of mortality in A. ipsilon, and the isolates GL (Heterorhabditis amazonensis), IBCBn-02 (S. carpocapsae) and IBCB-n05 (H. indica) caused 90 % mortality. In the tests of different concentrations, the isolate IBCB-n02 had CL99 estimated at a concentration of 140 IJs/ cm2, and the isolate IBCB-n05 had CL99 estimated at a concentration of 190 IJs/cm2. The most susceptible larval stages were the 3rd and 4th instars. In the in vivo test for production of A. ipsilon larvae, no difference was observed between the two isolates. In the greenhouse test, the isolate IBCB-n02 was the only one that differed from the control treatment.