Evaluation of augmentative biological control strategy against major borer insect pests of sugarcane—a large-scale field appraisal

Abstract

Abstract Background Biological alternatives to pesticides in agriculture do not harm non-targets organisms including natural enemies of insect pests. Experiments were conducted at sugarcane fields during 2015 to 2019 to assess large scale biocontrol practices, involving inundative releases of trichogrammatids against lepidopteran borers in comparison to conventional chemical-based farmers’ practice. Main body Eight releases each of Trichogramma chilonis Ishii and Trichogramma japonicum Ashmead were made at 50,000 ha−1 at 10 days interval for the management of sugarcane stem borer, Chilo infuscatellus Snellen and the sugarcane top borer, Scirpophaga excerptalis (Fabricius) (Lepidoptera: Crambidae), respectively. Likewise, 10–12 releases of T. chilonis were made at 50,000 ha−1 at 10 days interval for the management of sugarcane stalk borer, Chilo auricilius Dudgeon (Lepidoptera: Crambidae). The biocontrol intervention was compared with farmer’s practice (chemical control) in managing these borers. The results showed that farmers’ practices and biocontrol treated fields resulted in a lower incidence of C. infuscatellus (1.1, 2.9%) and S excerptalis (1.7, 3.9%) than the untreated control fields, wherein the mean per cent incidence of these borers (6.8, 8.5%) was significantly higher. The incidence of C. auricilius was also lower in augmented fields (2.8%) than untreated fields (7.3%). The yield data indicated that farmers adopting biocontrol practices were able to get comparable yield and benefit: cost ratio than farmers’ practice, both being better than untreated control. Moreover, in biocontrol fields, parasitism rate on the factitious host, Corcyra cephalonica Stainton cards was estimated. Conclusion Thus, the study highlights the significance of adoption of biocontrol-based technology over a long run to provide sustainable system of sugarcane insect pest management and economic benefits to the stakeholders.

Keywords

• Sugarcane
• Lepidopteran borers
• Augmentative biological control
• B: C analysis