author(s)
Arun Debbarma, J Jayaraj, P Chandramani, N Senthil, K Prabakaran and M Ananthan

abstract
The seasonal incidence of diamondback moth and its parasitoids was recorded since September, 2015 to December, 2017 in Theni and Dindigul districts of Tamil Nadu, India. During the periods of investigation, the larval parasitoid, Cotesia plutellae Kurdjumov (Braconidae: Hymenoptera) was recorded as dominant causing 32.85 per cent and 15.23 per cent parasitisation in unsprayed and sprayed field during 2015-2016 in Theni district whereas the parasitisation recorded in unsprayed and sprayed field of Dindigul district during 2016-17 were 34.48 per cent and 14.78 per cent respectively. This was followed by Oomyzus sokolowskii (Eulophidae: Hymenoptera) a larval-pupal parasitoid causing 27.08, 13.33 per cent and 28.07, 13.42 per cent parasitisation in unsprayed and sprayed field of Theni and Dindigul districts in the 2015-16 and 2016-17 respectively. Diadegma semiclausum (Ichneumonidae: Hymenoptera) a larval parasitoid activity was recorded in both districts and the intensity were low and ranged between 12.15, 5.39 per cent and 12.36, 5.41 per cent in unsprayed and sprayed field of above mentioned districts and season. Both the diamondback moth larva and Parasitisation was recorded maximum in unsprayed as compared to sprayed fields. The larval survivability and success of pupa was more on compact curd as compared to loose curd. The gravid female Cotesia plutellae were more active during dusk hour for seeking their host for oviposition and oviposits near the head region of II, III and IV instars larvae of diamondback moth. The plant age, larval population and natural enemies occurrence showed a positive significant correlation.