Incidence of invasive mealybugs, Phenacoccus solenopsis Tinsley and Paracoccus marginatus Williams & Granara de Willink (Hemiptera: Pseudococcidae) on Gymnema sylvestre (R. Br) and its natural enemies in the semi-arid region of India

Abstract

The invasive mealybugs, Phenacoccus solenopsis Tinsley and Paracoccus marginatus Williams & Granara de Willink (Hemiptera: Pseudococcidae) are causing significant damage to Gymnema sylvestre in the semi-arid region. This study highlights the nature of the damage, severity of mealy bugs and natural enemy complex association. The severity of infestation was maximum during 23rd and 22nd Standard Meteorological Weeks (SMW) (3.67 and 3.66) of 2019 and 2020, respectively. The pooled data of both the years revealed that temperature has a significant positive correlation and rainfall has a negative correlation towards the severity of the pest incidence with respective r-values of 0.678** and −0.05. A total of 19 different natural enemies identified belong to 7 families of 4 insect orders. Cheilomenes sexmaculata (Fabricius) was the most common predator and among the parasitoids, three species of primary parasitoids viz., Aenasius arizonensis (Girault) and Pseudleptomastix mexicana Noyes & Schauff (Hymenoptera: Encyrtidae) were more abundant. Besides, six species are hyperparasitoids viz., Aprostocetus sp, Chartocerus sp., Cheiloneurus sp., Homalotylus turkmenicus Myartseva, Marietta leopardina Motschulsky and Prochiloneurus sp. were recorded from primary parasitoids.