The Compatibility of Natural Enemies and Botanical for Management of Earias vittella (Fabricius) (Lepidoptera: Nolidae) and Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) in Bhendi Ecosystem

Abstract

Aims: The current study was conducted to know the compatibility of natural enemies and botanical for management bhendi fruit borers in the bhendi field.
 Study Design: Randomized Complete Block Design (RCBD).
 Place and Duration of Study: Experiment conducted during 2019-20 and 2020-21 at ICAR- National Bureau of Agricultural Insect Resources, Hebbal, Bengaluru, Karnataka, India. 
 Methodology: Two field tests were conducted at the entomological research farm, ICAR-NBAIR Bengaluru, Karnataka, India, to know the compatibility of the natural enemies (Trichogramma chilonis Ishii (Hymenoptera:Trichogrammatidae) , Chelonus blackburni (Cameron) and Bracon brevicornis (Wesmael) (Hymenoptera: Braconidae) and botanical (Neem oil 0.5%) for management of E. vittella and H. armigera on bhendi. Arka Nikita (IIHR) bhendi variety was used for the two trials with different treatments in four replication. The release rates of parasitoids were decided based on the previous parasitic potential studies.
 Results: In the first trial, among the treatments, a combination of T. chilonis + C. blackburni + B. brevicornis and C. blackburni + B. brevicornis recorded the lowest pooled mean larval population reduction over pre-treatment count of E. vittella and were on par with each other, recording 40.19% and 37.27%, respectively followed by T. chilonis + B. brevicornis (31.28%), C. blackburni (30.90%), B. brevicornis (28.64%), Neem oil 0.5% (27.71%), Neem oil 0.5% + B. brevicornis (25.46%) and T. chilonis (25.32%). A similar trend was also observed in combination of T. chilonis + C. blackburni + B. brevicornis and C. blackburni + B. brevicornis against H. armigera, which accounted for 47.19% and 37.22% of reduction over pre-treatment count in the respective treatment combination of parasitoids. The next best treatments were T. chilonis + B. brevicornis (28.21%), C. blackburni (26.56%), B. brevicornis (22.21%), Neem oil 0.5% (20.37%), T. chilonis (17.31%) and Neem oil 0.5% + B. brevicornis (16.07%)
 Conclusion: From this study we recommend that, for bhendi fruit borers management, release of parasitoids like T. chilonis + C. blackburni + B. brevicornis at 50,000+1000+1000 adults/ha, respectively in bhendi field starting from 35 DAS at 15 days’ intervals of duration, two-time release of parasitoids is enough later, they have augmented and reduce the population of fruit borer larvae effectively.