Biology of Mexican Beetle (Zygogramma bicolorata Pallister)--A Biocontrol Agent for Managing Parthenium hysterophorus L

摘要

Parthenium (Parthenium hysterophorus L.) popularly known as carrot grass, tara grass, congress or sada tupi has emerged as one of the worst weeds in India due to its harmful effects on man and animals. Presently, the weed has spread to almost all places except at high altitude, high arid zone and near the seacoast. Parthenium has been considered as one of the greatest source of dermatitis, asthma, nasal-dermal and nasal-bronchial types of diseases resulting from parthenin. Mexican beetle (Zygogramma bicolorata Pallister.) has been used as an effective bio-control agent in managing parthenium weed in other countries. The present investigation was undertaken to study the biology of Mexican beetle (Zygogramma bicolorata Pallister., Chrysomellidae, Coleoptera) in India. Biology of the Mexican beetle was studied under laboratory conditions at constant temperature (25 plus or minus 1C) and relative humidity (70 plus or minus 5%). The average premating, mating, pre-oviposition and oviposition period in females were 6.0 (5--7), 43.4 (12--61), 8.9 (7--11) and 41.1 (11--67) days, respectively. Average adult longevity was 84.8 (55--95) days in males and 57.8 (20--91) days in females. Average fecundity was 725.5 (92--1415) eggs/female. The incubation, larval and pupal periods were 3.0, 10.7 and 10.9 days on an average. Larvae passed through four instars; the average duration being 2.9(2--4), 2.4 (2--3), 2.4 (2--4) and 3.0 (2--4) days, respectively for the four instars. The total duration of life cycle was found to be 24.7 (24--25) days.