Abstract
The research work on the evaluation of yard long bean genotypes for resistance to legume pod borer, Maruca vitrata F. and it's biorational management was carried out under field and laboratory conditions in the Department of Entomology, Bangladesh Agricultural University, Mymensingh during 2014-15 to 2016-17 crop season. Nine (9) genotypes of yard long bean were evaluated and reacted distinctly to M. vitrata with significantly different levels of infestation to flowers, pods and yield. The genotype Long Red Mollika was categorized as moderately resistant to legume pod borer in both kharif and rabi seasons. Genotype YL 305 was found susceptible in both the seasons. The plant attributes, both vegetative and reproductive did not show any significant correlation in favour of resistance to M. vitrata. Yard long bean genotypes also did not show resistant reaction to M. vitrata in respect of sugar and phenol content but particularly protein showed antibiosis against M. vitrata. Microbial pathogens, namely Bacillus thuringiensis and Beauveria bassiana had comparatively less performed at the field condition in decreasing the flower and pod infestation, increasing pod yield of yard long bean by suppressing the attack of M. vitrata in comparison to Notro 505EC. Microbial derivative emamectin benzoate @ 1.0 g/L was superior to spinosad and standard insecticide Nitro 505EC in respect of benefit cost ratio and toxic action on M. vitrata and it reduced 55.52 and 68.37 percent flower and pod damage resulting 47.90 percent increasing pod yield. Insect growth regulator buprofezin @ 0.5 ml/L exhibited better performance than lufenuron and standard insecticide Nitro 505EC in respect of benefit cost ratio and toxic action on M. vitrata and the flower and pod damage accounted for 61.96 and 67.46 percent reduction resulting 40.11 percent increasing pod yield. Azadirachtin 1% @ 1.0 ml/L at 7 days intervals on the yard long bean showed better performance in respect of benefit cost ratio and in the reduction of flower and pod damage of 59.94 and 66.10 percent with significantly higher pod yield of 51.91 percent. Among the eight different biorational based IPM packages the integration of variety (Long Red Mollika), hand picking and spray of emamectin benzoate @ 1.0 gm per litre of water at 7 days intervals had comparatively better performance in the reduction of 80.63 percent flower, 83.63 percent pod damage, 60.24 percent pod yield increase and benefit cost ratio of 1.74. Therefore, emamectin benzoate, buprofezin and azadirachtin individually or the IPM package of the integration of variety (Long Red Mollika), hand picking and spraying of emamectin benzoate could be recommended to protect yard long bean from the attack of M. vitrata ensuring higher yield.