Life-tables of Chilo partellus (Swinhoe) infesting rabi Maize

Abstract

Chilo partellus (Swinhoe), the maize spotted stem borer, remains a highly destructive pest capable of causing drastic yield deficits across diverse agricultural zones. Formulating ecologically sustainable pest management protocols requires a clear understanding of its demographic dynamics and natural mortality pressures. Since localized field-based life table evaluations for C. partellus during rabi maize cultivation in the Marathwada region are scarce, this study was undertaken to bridge the gap. Field trials were carried out in the 2020–21 rabi season at the Post Graduate Experimental Field, Department of Entomology, College of Agriculture, VNMKV, Latur. Two distinct pest generations were observed during the crop cycle. In the first and second generations, early-stage larval mortality caused by natural predators and harsh weather conditions reached 6.24% and 5.87%, respectively. Parasitization by the braconid wasp Cotesia flavipes was responsible for 6.66% mortality in the initial generation. During the late larval phase of the first generation, combined abiotic factors and predation accounted for 6.24% mortality. Pupal mortality varied drastically, recorded at 28.57% in the first generation and 6.66% in the subsequent generation, with predation and adverse weather driving 11.11% and 16.12% of this mortality, respectively. The first generation exhibited a trend index of 1.60 and a survival rate of 0.62, whereas the second generation yielded values of 0.00 and 0.82, respectively. These observations underscore the critical role of natural bioagents and climatic pressures in regulating C. partellus populations. The data provides a foundational baseline for optimizing ecologically conscious Integrated Pest Management (IPM) in rabi maize by prioritizing the protection of indigenous natural enemies.