aProject Directorate of Biological Control, H. A. Farm Post, Bangalore560024, Karnataka, India.
bDepartment of Entomology, University of Agricultural Sciences, Dharwad580007, Karnataka, India.
cDepartment of Entomology, College of Agriculture and Regional Agricultural Research Station, Raichur584101, Karnataka, India.
dDepartment of Entomology, University of Agricultural Sciences, Bheemarayanagudi585287, Karnataka, India.
eDepartment of Entomology, Tamil Nadu Agricultural University, Coimbatore641003, Tamil Nadu, India.
fDepartment of Entomology, Anand Agricultural university, Anand388001, Gujarat, India.
Multiple insecticides tolerant strain of Trichogramma chilonis Ishii (MITS-Tc), tolerant to the major insecticides -endosulfan (chlorinated hydrocarbon), monocrotophos (organophosphate) and fenvalerate (synthetic pvrethroid) was developed in the laboratory and was field evaluated compared to insecticide susceptible strain (ISS-Tc), insecticide control practice (ICP) and untreated control (L/C) against American bollworm, Helicoverpa armigera (Hiibner) on cotton at different geographical locations in India for the years 2002-03 and 2003-04. The parasitisation of H. armigera eggs was significantly higher in MITS-Tc, Dharwad (25.4%), Gulburga (43.0%) and Coimbatore (8.4%) compared to ISS-Tc, ICP and UC. respectively during 2002-03 and 2003-04 seasons per cent egg parasitism in MITS-Tc was significantly higher in Raichur (11.3%) and Coimbatore (22.1%) compared to other treatments. However at Anand, it was at par between MITS-Tc and ISS-Tc treatments but significantly higher than ICP and UC treatments. The mean lan'al population was significantly less in MITS-Tc plots when compared to larval population in ISS-Tc, ICP and UC plots at Dharwad, Gulbarga and Anand locations and was at par with ISS-Tc at Coimbatore during 2002-03 and 2003-04 seasons, lan'al population in MITS-Tc was significantly lower compared to other treatments at Raichur and was at par at Coimbatore and Anand amongst all treatments but significantly superior to UC. The per cent boll damage was significantly lower in MITS-Tc treatment plots as compared to other treatments in Dharwad, Gulbarga and Coimbatore during 2002-03 and at Coimbatore during 2003-04 seasons. The yield recorded in MITS-Tc was significantly higher than other treatments at all five locations in 2002-03 and 2003-04 seasons, Integration of MITS-Tc with insecticides also provided increused monetary benefits to the farmers. Utilization of MITS-Tc in management of American bollworm on cotton and increased profitability is discussed.
Multiple insecticide tolerant strain, insecticide susceptible strain, Trichogramma chilonis, Helicoverpa armigera, cotton
