Bio-ecology and management of arecanut scale, Parasaissetia nigra (Neitner) and mealybug, Dysmicoccus brevipes (Cockerell)

Populations of P. nigra and D. brevipes were higher during summer (March-May, 2002). However, the populations of both the pest species remained low during the rainy and winter season (July-December). Similar trend was noticed with their natural enemiesviz., Anagyrus sp., Cryptolaemus montrouzieri (Mulsant) and Scymnus sp. The fecundity of both P. nigra and D. brevipes was high during summer months with a maximum of 183.24 ± 37.52 and 136.20± 28.09 no./female, respectively. Parasaissetia nigra reproduced parthenogenetically; there being no males, with a total life cycle of 75.24 days. Dysmicoccus brevipes had three nymphal instars infemale, while, the males had three nymphal and one pupal instar. Oecophylla smaragdina Smith was the major ant species associated with P. nigra and D. brevipes on arecanut. Among the different insecticides and plant products tested against P. nigra and D. brevipes, neem oil at 3 per cent was effective upto 21 days (5.23no./nut), as compared to standard check chlorpyriphos (10.53 no./nut). From the study it was clear that neem oil is a suitable substitute in controlling P. nigra. Similarly, neem oil at 3 per cent significantly reduced the population of D. brevipes (1.07 no./nut) which is at par with pongamia oil at 3 per cent (1.13 no./nut) when compared to untreated check (4.53 no./nut).