Ecological studies on Trichogramma japonicum (Ashmead), an egg parasitoid of lepidopteran pests

Effect of low storage temperature and three rearing temperatures on Trichogramma japonicum (Ashmead) and its host searching ability revealed that seven-day old Corcyra cephalonica (Stainton) eggs parasitized by T. japonicum can be stored in refrigerator (4°C) up to 9 days without effecting their emergence, parasitization as well as the emergence and sex ratio of the progeny. Both low (below 25°C) as well as very high (above 30°C) temperatures were detrimental to the parasitoid while 25±1°C was found to be ideal in terms of the parasitization efficiency, emergence and their longevity. However, the rearing temperatures up to five generations did not affect their sex-ratio. The maximum parasitization by T. japonicum was recorded at lm distance during April to October but the effective host searching range was up to 4m from the release point. Beyond 4m the parasitism was quite low and was recorded up to a maximum of 9m distance especially in October.