SEASONAL INCIDENCE OF MEALYBUG SPECIES AND THEIR MAJOR PARASITOIDS ON COTTON (GOSSYPIUM SP. L.) IN COIMBATORE, TAMIL NADU
The field experiment on seasonal incidence of mealybug species of cotton was conducted in Tamil Nadu Agricultural University during 2016-2017. Results showed four mealy bug species such as Phenacoccus solenopsis (Tinsley), Maconellicoccus hirsutus (Green), Ferrisia virgata (Cockerell) and Paracoccus marginatus (Williams & Granara de Willink). Among them, peak population of Phenacoccus solenopsis (400.75 insects/plant) was recorded in October and that decreased slowly during January (100.6 insects/plant) and there was much reduced/less population during February - March. Correlation analysis between weather parameters and mealy bug activity indicated that there was positive correlation with maximum temperature, minimum temperature, relative humidity and negative correlation with rainy days. The major parasitoids commonly found attacking mealybugs in the experimental field were Aenasius arizonensis Girault, Promuscidea unfasciati Girault and Acerophagus papayae Noyes & Schauff. The assessment of mealybug population and the level of parasitization of the three parasitoids were carried out based on the adult emergence from the sampled parasitized mealybugs. The parasitism of mealybug by Aenasius arizonensis was the highest in October which decreased gradually during January.
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