Influence of resistant and susceptible pigeonpea cultivars on the parasitization efficiency of some parasitoids on podfly, Melanagromyza obtusa (Malloch).

摘要

Three parasitoids, viz. Ormyrus orientalis, Euderus agromyzae and Eurytoma ranjithi, parasitized the podfly Melanagromyza obtusa on all the three pigeon pea cultivars (SL12-1, Bahar and NA1) in a field experiment conducted in Kanpur, Uttar Pradesh, India, during the 2000-01 and 2001-02 cropping seasons. Parasitization increased with the increase in pest population irrespective of the parasitoid species. Ormyrus orientalis was recorded as the key parasitoid. There was a significant effect of resistant and susceptible cultivars on parasitization of podfly. The mean parasitization by all the three species in 2000-01 was 24.0% on NA1 followed by Bahar (22.5%) and SL12-1 (8.4%). Similarly, in the following year, the mean parasitization was 25.0% on NA1 which was on par with Bahar (24.3%) but significantly superior (p=0.05) to SL12-1 (9.3%). A distinct variation in the population of M. obtusa with respect to pigeon pea cultivars was observed; however, the oviposition trend recorded at weekly interval was almost the same. The average oviposition was 14-15% in the case of the susceptible cultivars (Bahar and NA1), whereas the resistant cultivar SL12-1 exhibited only 4% oviposition by podfly. The results clearly indicated that greater parasitism of M. obtusa occurred on susceptible genotypes than resistant cultivar..