Scope for Biological Control of Powdery Mildew of Mulberry with Illeis bielawskii Ghorpade, a Mycophagous Coccinellid

Abstract

Mulberry powdery mildew disease caused by Phyllactinia corylea (Pers.) Karst is a production constraint during winter months. A mycophagous coccinellid, Illeis bielawskii Ghorpade was found to be associated with the disease. Population of I. bielawskii among mulberry varieties ranged from 2.47numbers/plant (MR2) to 15.92/plant (Kanva 2). The egg, larval and pupal periods were 2.97, 9.00 and 3.22 days, respectively. The adult longevity was 20-25 days. The grubs and beetles actively fed on the fungus and the rate of feeding was found to be highest in adult (118.91 cm²), followed by fourth instar grub (43.28 cm²), Safety studies conducted revealed that there was no significant difference in hatching of eggs between control (no insecticide treatment) and the insecticide treatments, viz., malathion, methyl demeton and dichlorvos, However, a mortality of 50 and 46.67 per cent was observed when grubs were fed with mildew affected leaves treated with malathion and dichlorvos. To be effective as a biocontrol agent, it should not behave as a vector, Studies conducted on disease-vector relationship revealed that I.bielawskii does not have any significant role in disseminating the powdery mildew pathogen, P. corylea