Woolly whitefly, Alerurothrixus floccosus (Maskell) (Homoptera, Aleyrodidae) as a new invasive pest and efficacy of certain insecticides on lemon trees at Kafr El-Sheikh

Abstract

The current study was carried out at lemon orchards at (Sakha and Motobus) Districts, Kafr EL-Sheikh Governorate in 2024 to monitor the population dynamics of Alerurothrixus floccosus (Maskell), as an emerging pest in lemon orchards A. floccosus showed a fluctuated pattern, with peaks in late July and early August (40.7 and 40 adults, respectively. Populations of nymphs took the same trend, but with lower population densities. The predator, Amblyseius spp population remained relatively low throughout most of the observation period, with a slight increase towards the end of observation period, particularly during October and November. The study found that thiamethoxam and formetanate were the most effective treatments for controlling A. floccosus nymphs on citrus lemons. Spirotetramat and Flonicamid showed quick and long-lasting effects, while thiamethoxam had the highest initial kill in adult whitefly. Spinetoram performed well initially but had a moderate residual effect. Formetanate had the least initial kills and the least residual effect. Future studies should focus on optimizing these compounds for effective lemon trees management.