Effect of controlled temperatures on infection, development and multiplication of Steinernema asiaticum on Plutella xylostella (L.) larvae

Effect of varying temperatures on infection, development and multiplication of Steinernema asiaticum on diamondback moth, Plutella xylostella larvae was investigated and the results revealed mortality of P. xylostella larvae due to S. asiaticum was negligible at 10 and 15°C but increased significantly to 27.50 and 30% at 25 and 30°C, respectively. It further increased significantly at 35°C (44.46%) and peaked at 40°C (83.25%). However, temperature itself at 35 and 40°C caused insect mortality to 13.93 and 60.25%, respectively. Nematode was not able to multiply at 10, 15 and 40°C. Maximum IJ’s recovery recorded at 30°C (279) and 35°C (228) and the two were on par. The nematode took least number of days for next generation of IJ’s at 35°C (5-6 days) followed by 30°C (6-8 days) therefore is more favourable for mass multiplication of S. asiaticum to be used as an effective bio-control agent.