Do Cultivar, Watering and Plant Distance Impact Aphids and Their Natural Enemies in Chili (Capsicum chinense Jacq.)?

Abstract

Chilies are being increasingly favored worldwide, with an increasing growing area. As limited information is available about the population dynamic of arthropod communities in chilies under field conditions, the aim of our survey was to observe aphids and their natural enemies under various agrotechnological factors to improve IPM for chilies. The Yellow Scotch Bonnet (YSB) and Trinidad Scorpion Butch T (TSBT) chili varieties were investigated. Two plant spacings (30 vs. 40 and 40 vs. 60 cm in YSB and TSBT, respectively) and two watering rates (40 min/day; 20 min every second day) were applied with three replicates. Ten plants per plot/date were checked visually from July to September each year. In 2019, significantly more Chrysopidae eggs and significantly fewer Coccinellidae eggs were found under less watering. The number of Chrysopidae larvae and Coccinellidae pupae and larvae was significantly higher, whereas that of Chrysopidae eggs and Thomisidae individuals was significantly lower in the less-irrigated plots in 2021. In the same year, significantly more Coccinellidae adults were detected in the TSBT cultivar, and the number of Chrysopidae eggs and larvae and Coccinellidae pupae was significantly lower under decreased plant spacing. Predators preferred plots with an increased plant distance and plants with higher aphid pressure.