Cotton is susceptible to a wide variety of insect pests, among which Mealybug, Phenacoccus solenopsis is the most prominent insect pest. A field study was carried out during Kharif 2023 and 2024 at the Experimental Farm, S.K.N. College of Agriculture, Jobner (Rajasthan) to assess the seasonal incidence of the P. solenopsis on Bt cotton and its relationship with prevailing weather parameters. The pest infestation began in the third week of August (34th SMW) with an initial population of 0.60 and 0.92 mealybugs per 10 cm apical shoot in 2023 and 2024, respectively, and continued until the end of the crop season. The peak incidence was recorded in the last week of October (44th SMW), reaching 82.12 and 76.28 mealybugs per 10 cm shoot in 2023 and 2024, respectively. Correlation analysis revealed a significant negative association between mealybug population and relative humidity (r = -0.58 in both years), and a significant positive correlation with sunshine hours (r = 0.49) in 2024. Other weather parameters such as maximum and minimum temperatures and rainfall showed non-significant correlations. These findings indicate that low humidity and prolonged sunshine hours favour the multiplication and population buildup of P. solenopsis in the semi-arid climatic conditions of Rajasthan

Phenacoccus solenopsis, Bt cotton, population dynamics, weather parameters, correlation, Rajasthan

The present study clearly established the seasonal incidence, population dynamics, and correlation of Phenacoccus solenopsis with weather parameters and its natural enemies on Bt cotton during Kharif 2023 and 2024. The mealybug infestation initiated in the third week of August and persisted until December, peaking in late October. A significant negative correlation was observed with relative humidity, while maximum temperature and sunshine hours showed a variable but generally positive influence on population buildup. Among natural enemies, Coccinellids, Spiders, and Chrysoperla spp. played a vital role in regulating mealybug populations, all showing significant positive correlation with pest density, especially Chrysoperla spp., which exhibited the strongest association. These findings underline the importance of favorable weather conditions in pest outbreaks and emphasize the role of natural enemies in suppressing mealybug populations. Hence, the integration of these natural enemies into pest management strategies can offer effective, eco-friendly control of mealybugs, reducing reliance on chemical pesticides and supporting sustainable cotton production

Sheetal Kumawat, Akhter Hussain, Shankar Lal Sharma, B.L. Naga, J.K. Bana, Arvind and Raj Kumar Bajya (2025). Population Dynamics of Mealybug, Phenacoccus solenopsis and its Natural Enemies in Bt Cotton. Biological Forum, 17(8): 45-49