Journal of Global Agriculture and Ecology

Parthenium hysterophorus also known as Congress grass, is a prolific weed belonging to Asteraceae family, and approximately two million hectares of land in India have been infested with this herbaceous menace. It can only be managed effectively by developing an integrated approach involving many options in combination. The biological control of Parthenium has been explored through a leaf beetle Zygogramma bicolorata Pallister, at Baru Sahib, Himachal Pradesh. The Z. bicolorata is considered as safe biocontrol agent but till now it was not well established and spread in the Himachal Pradesh. Therefore, present study investigated the life cycle, feeding behavior and natural enemies of the beetle in the region. The female beetle lay about 650-700 eggs and larvae hatched after 36 to 72 hrs, which feed on the Parthenium for 12 to 16 days. After 4^th instar, it enters the soil and pupates below. The beetles emerged after 8-10 days and completed their life cycle in 25 to 28 days. Both the adults and larvae were capable of feeding on the Parthenium leaves but only 15-20% on the flowers. Henceforth, we also investigated the net house condition for rearing the Zygogramma beetles in natural environment and studied different factors that limit the population of the beetles in the natural surroundings. The population of the beetles was not increasing in the natural environment of Himachal Pradesh because of the different natural enemies (Rodolia cardinalis, Perillus bioculatus, Gryllus sp. etc.) that feed on the eggs and larvae of the beetles.