Spatial variation of important mulberry pests and their natural enemies

Abstract

Mulberry is a silkworm food plant ( Bombyxmori . L) that is seriously affected by many insect pests. The incidence of Diaphania pulverulentalis (Hampson), Maconellicoccus hirsutus (Green), Paracoccus marginatus (Williams and Granara de Willink), Aleurodiscus dispersus (Russels) and Pseudodendrothrips mori (Niwa) and their natural enemies, viz . coccinellids and spiders (/100 plants), were observed through survey and surveillance for 3 months. In February 2013, the incidence of insect pests in Vaikkalpattarai and Reddipudur villages (India) was: D. pulverulentalis, 1.20 and 0.85%; P. marginatus , 6.80 and 33.10%; P. mori 42.98 and 45.50%, respectively. Further, the infestation of M . hirsutus (1.40%) and A. dispersus (59.72%) was also observed in February at Vaikkalpattarai. The population of coccinellids was high in December (1.02 and 0.84/100 plants), but the spider population was even higher in February and January (1.04 and 1.81/100 plants). Population of pests had a significant positive correlation with relative humidity. The population of coccinellids and spiders have positive correlation with temperature and mulberry pests infestation. The natural enemies observed in the study were mostly the ladybird beetles, Psyllobora bisoctonotata and unidentified species of spiders.