Bionomics of Anomala dimidiata Hope. (Coleoptera: Rutelinae)–A Devastating Agri-Horticultural Pest in Western Himalayas

Abstract

In Western Himalayas, Anomala dimidiata Hope. is a very important pest of agri-horticultural crops, forest trees, nurseries, and pasture lands. Its subterranean grubs feed on the tender roots of silvi-agri-horticultural plants. The adult beetles defoliate a number of fruit and forest trees. Under laboratory conditions, a female lays 12.5 ± 6.13 eggs in the soil, which hatch in 12.70 ± 1.41 days, during its life span. The grub stage lasts in 246.2 ± 13.07 days. Pupation takes place in the soil. Pupal stage lasts in 14 ± 1.54 days. The adult stage remains in the soil until the onset of rains. The beetles live for 25 to 84 days after their emergence from the soil. The female beetles live for 57.8 ± 14.79 days, while male 45.3 ± 13.54 days. Under laboratory conditions, the total duration from egg to adult stage took 251 to 298 days, with an average of 275.5 ± 15.63 days. Female beetles outnumbered males; the former constituted about 58 percent of the total population. The longevity of adults varied from 25 to 84 days. The longevity of male beetles ranges from 25 to 68 days with an average of 45.3 ± 13.54 days, while in the case of females, it ranges from 26 to 84 days with an average of 57.8 ± 14.79 days. The peak emergence period is the 2nd fortnight of June to the 2nd fortnight of July. The pests complete one generation in a year.