Seasonal abundance ofScaphisoma tetrastictumChamp on oyster mushroom and its relation to meteorological factors

Abstract

A study on the seasonal incidence of the beetle Scaphisoma tetrastictum Champ and the relationship of various meteorological factors with its incidence in oyster mushroom ( Pleurotus ostreatus Jacq. Ex Fr.) was conducted in the Department of Plant Pathology, Assam Agricultural University, Jorhat (India) during 1999–2000. Seasonal variation in the population density of adult beetles and per cent fruit body infestation by the adults and grubs were observed. Incidence of the beetle was recorded from March to November 1999 revealing the highest number (12.35) of adults per fruit body and per cent infestation (29.96) during July, 1999. The mushroom remained free from beetle incidence during the winter months. Beetle population per fruit body (10.43) and extent of infestation (26.03%) were higher during monsoon (June to August) where as the pre-monsoon period (March to May) recorded the beetle population and per cent infestation of 4.64 and 9.61%, respectively. Beetle population showed positive significant correlations with maximum ( r = 0.7460, P < 0.05) and minimum temperature ( r = 0.6884, p < 0.05) and number of rainy days ( r = 0.9102, p < 0.01). Per cent fruit body infestation by the beetle exhibited positive significant correlations with maximum temperature ( r = 0.8032, p < 0.05), minimum temperature ( r = 0.7666, p < 0.05), total rainfall ( r = 0.6823, p < 0.05) and number of rainy days r = 0.9299, p < 0.01).