Resistance development in Cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) to insecticides from Organophosphate, Thiadiazines and Thiourea derivatives

Cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) is a highly invasive pest of cotton and other economically important agri-horticultural crops, worldwide. Majority of the cotton growers rely on chemical insecticides to control this pest. Indiscriminate use of insecticides has lead to development of resistance against some insecticides in recent years. Aiming to investigate the resistance development in P. solenopsis to some of the commonly used insecticides, Phenacoccus solenopsis colonies were collected from infested plants of cotton from four different locations namely Yavatmal, Wardha, Amravati and Akola districts of Vidarbha region of Maharashtra, India. The mealybugs were cultured on potato spouts in the laboratory for one generation to eliminate intermittent field infection of natural enemies and bio-assayed by leaf dip method in the laboratory. Results of bioassay indicated very high (RF 378.29) level of resistance against Thiadiazines (buprofezin) in mealybug population collected from Amravati, whereas resistance was found negligible at other locations. Low to very low level of resistance was recorded against organophosphates (monocrotophos, chlorpyrifos, quinalphos and acephate) and Thiourea derivatives (diafenthiuron) from all the locations. The results of the present study provide valuable information regarding selection of appropriate insecticides as one of the components of integrated management of P. solenopsis.