Seasonal population trend and relative occurrence of pests and their natural enemies among cotton species and cultivars in India

Abstract Background Cotton crop is infested by numerous arthropod pests from sowing to harvesting, causing substantial direct and indirect yield losses. Knowledge of seasonal population trends and the relative occurrence of pests and their natural enemies is required to minimize the pest population and yield losses. In the current study, analysis of the seasonal population trend of pests and natural enemies and their relative occurrence on cultivars of three cotton species in Central India has been carried out. Results A higher number and diversity of sucking pests were observed during the vegetative cotton growth stage (60 days after sowing), declining as the crop matured. With the exception of cotton jassid (Amrasca biguttula biguttula Ishida), which caused significant crop damage mainly from August to September; populations of other sucking insects seldom reached economic threshold levels (ETL) throughout the studied period. The bollworm complex populations were minimal, except for the pink bollworm (Pectinophora gossypiella Saunders), which re-emerged as a menace to cotton crops during the cotton cropping season 2017–2018 due to resistance development against Bt-cotton. A reasonably good number of predatory arthropods, including coccinellids, lacewings, and spiders, were found actively preying on the arthropod pest complex of the cotton crop during the early vegetative growth stage. Linear regression indicates a significant relationship between green boll infestations and pink bollworm moths in pheromone traps. Multiple linear regression analyse showed mean weekly weather at one- or two-week lag periods had a significant impact on sucking pest population (cotton aphid, cotton jassid, cotton whitefly, and onion thrips) fluctuation. Gossypium hirsutum cultivars RCH 2 and DCH 32, and G. barbadense cultivar Suvin were found susceptible to cotton jassid and onion thrips. Phule Dhanvantary, an G. arboreum cotton cultivar, demonstrated the highest tolerance among all evaluated cultivars against all sucking pests. Conclusion These findings have important implications for pest management in cotton crops. Susceptible cultivars warrant more attention for plant protection measures, making them more input-intensive. The choice of appropriate cultivars can help minimize input costs, thereby increasing net returns for cotton farmers.