BIOLOGY AND SEASONAL INCIDENCE OF MEXICAN BEETLE ZYGOGRAMMA BICOLORATA PALLISTER ON PARTHENIUM IN NEW ALLUVIAL ZONE OF WEST BENGAL

摘要

Parthenium hysterophorus Linn. (Heliantheae; Asteraceae) commonly known as parthenium weed, congress grass, fever few, rag weed, star weed, gajar ghas or white top is an annual herbaceous poisonous and problematic weed. Various chemicals control suchweeds effectively but continuous use causes the pollution hazards. Therefore, weed management strategy needs to be shifted towards non-chemical methods. Managing weeds by biological means is less expensive, permanent and pollution free. Considering this,efforts on biological control of this weed was first initiated in 1983 with the introduction of Mexican beetle, Zygogramma bicolorata in India (Jayanth and Nagarkatti, 1987). It is found in some pockets of Murshidabad district of West Bengal feeding onparthenium voraciously. As sufficient information on the ecology of this beetle is still not available from West Bengal, present study on its biology and seasonal incidence were undertaken.