Pantnagar Journal of Research

Abstract

The papaya mealybug, Paracoccus marginatus Williams and Granara de Willink, is a small hemipteran pest that attacks important tropical fruits, vegetables and ornamentals. In the present study, the population dynamics of P. marginatus and its natural enemies, were carried out in randomly selected papaya trees in Pantnagar from August 2023 to July 2024. Study revealed that infestations began in the second fortnight of August 2023, with the pest infestation (1.8 mealybugs/5cm²/leaf/plant). The population was low during the first fortnight of January but peaked during the first fortnight of April 2024. During the second fortnight of May, the highest level of P. marginatus infestation was noticed (147.40 mealybugs/5cm²/leaf/plant), but the population declined during July. The study also examined the relationship between weather parameters and insect population, indicating a significant positive correlation between maximum, minimum temperature, sunshine hours, and the pest. The peak population of coccinelid predators like Scymnus frontalis, Brumoides suturalis and Cryptolaemus montrouzeiri with 7.0, 3.6, and 3.8 adults/leaf/plant population were noticed in between second fortnight of April to second fortnight of June. Thereafter, a gradual decline in the population of all three natural enemies was noticed in July. Weather parameters like maximum, minimum temperature and sunshine hours exhibited a positive correlation with the natural enemies, while the morning, evening relative humidity and rainfall showed a negative correlation. On correlating the natural enemies with the population of P. marginatus, all three coccinellids exhibited a positive correlation, displaying a substantial positive connections with the population of P. marginatus.