Tritrophic interaction in the management of Helicoverpa armigera Hubner on cotton and sunflower using Chrysoperla carnea Stephens

Abstract

The investigations on ovipositional preference studies indicated that when compared newlineacross the different stages (Vegetative, flowering and boll formation ) the mean number of newlineegg laying by C. carnea in absence and presence of H. armigera was significantly highest on newlineDHH-543 and it laid significantly lower number of eggs on PA -255 and Abhadita. While newlineH. armigera laid significantly higher egg load on Sahana and least on DB -3-12 followed by newlineAbhadita. Among the different stages of cotton genotypes, C. carnea both in presence and newlineabsence of H. armigera laid more number of eggs at flowering followed by boll formation newlinestage, while H. armigera also followed the similar trend in its egg laying pattern. When newlinecompared across the stages of sunflower, the mean number of eggs laid by C. carnea in newlineabsence and presence of H. armigera was significantly highest on KBSH-1 and Morden and it newlinelaid least number of eggs on VRF-21 and DSF-2, whereas H. armigera laid significantly newlinelower number of eggs on VRF-21. Among the stages, C. carnea in absence and presence of newlineH. armigera laid more eggs at flowering stage followed by capitulum formation stage. H. newlinearmigera also followed the similar trend in its egg laying pattern. newlineBehavioral response of C. carnea using eight arm olfactometer indicated that the mean newlineorientation response of C. carnea towards the extract of DHH-543 and DHH-11 was newlinesignificantly more and least response was recorded towards the extract of DB -3-12. In case newlineof sunflower, the response was more towards the extract of KBSH-1, Morden and RSFH-1 newlineand it was lowest on VRF -21 and DSF-2. Further, the response of C. carnea towards the newlineextract of H. armigera scales at 0.5 per cent and 100 eggs /10ml of hexane was higher than newlineits lower concentrations. newlineThe feeding potential of chrysopid species on H. armigera eggs on different genotypes newlineof cotton was significantly higher on DHH-543, DLSA-17, Abhadita, DHH-11, MCU-5 and PA- newline255. Whereas in case of sunflower genotypes their feeding potential was significantly higher newlineon KBSH-1, morden a