Vol. 12, Issue 4 (2023)

Author(s):
Samik Chowdhury, T Boopathi, Hirak Chatterjee and Ardhendu Chakraborty

Abstract:
Field experiments were conducted in 2017-18 and 2018-19 at the ICAR Research Complex for NEH Region, Mizoram Centre, Kolasib, Mizoram to develop ecological engineering cropping systems for non-rice crops such as cowpea, pigeon pea, sesame, okra, eggplant, and chilli as border crops with the main crop rice (Gomati Dhan). These systems aimed to improve entomophages and suppress insect-pests in the rice ecosystem while maintaining zero insecticide conditions. Ecological engineering parameters such as pest defender ratio, occurrence ratio (OR) of entomophages, preference ratio (PR), biodiversity indices (species diversity, richness, and evenness) of entomophages and insect-pests, and cost benefit ratio (CBR) were assessed for all cropping systems. The population of Micraspis crocea (Mulsant) on rice was maximum as influenced by non-rice border cropping systems like, (rice + pigeon pea) and (rice + cowpea). However, (rice + sesame) (rice + okra), (rice + eggplant) and (rice + chilli border cropping systems affected the population of entomophages moderately than rice alone. Minimum population of Cnaphalocrocis medinalis was recorded in, (rice + pigeon pea) and (rice + sesame) bund system as compared to rice alone which registered maximum population and damage., Further, moderate population and damage of pests was registered in (rice + cowpea), (rice + okra) (rice + eggplant) and (rice + chilli) border cropping systems. Pest defender ratio was maximum on (rice + pigeon pea) and (rice + sesame) (1: 4.94, and 1: 4.73) border cropping systems followed by (rice + cowpea) (1. 3.27), (rice + okra) (1: 2.71), (rice + eggplant) (1: 2.60) and (rice + chilli) (1: 2.45) border cropping systems when compared to rice alone (1: 1.78). Highest OR of entomophages; minimum PR of pests; maximum species diversity, richness and evenness for entomophages and insect-pests; maximum yield; and higher CBR were estimated on (rice + pigeon pea), (rice + cowpea) and (rice + sesame) border cropping systems than on (rice + okra), (rice + eggplant), (rice + chilli) and rice alone cropping systems.