STUDIES ON THE PEST STATUS AND SEASONAL ABUNDANCE OF DIFFERENT INSECT PESTS IN BRINJAL AT GAZIPUR.

Abstract

Several experiments have been undertaken to determine the pest status and seasonal abundance of different insect pests in brinjal at (iazipur during November 2005 to September 2006 in the Entomology Division Experimental field, BAR]. Ciazipur. Five species of insect pests were recorded in the brinjal field during the study period Among the insect pests. Brinjal shoot and fruit borer, Leucuuxles urbana/is (Lepidoptera: Noctuiidae) was appeared first followed by jassid. Arnarasca clevasians (Homoptera: Cicadellidac). Whitefly, Bemasia tabaci (Hemiptera: Alevrodidae), two species of epilachna beetle, Epi/achna ;iintiocpuctata & it /2-punctata (C'oleoptera:coccinellidae and Aphids, A,this gussv)ii (Hemiptera: Aphididae). Among the five different pests recorded in the brinjal fields at Gazipur, brinjal shoot and fruit borer (BSFB) was the predominant one followed by jassid, whiteflv, epilachna beetle and aphids. Year round infestation of BSFE3, both in shoot and fruit was observed in the experimental plots. The highest infestation of BSFB was observed during hot and humid periods of the year (June - September). Except the thy months of the year (February April), the infestation of jassid was not so high. Highest infestation of epilachna adult was observed during the month of December (0068 per leaf), while that of epilachna larvae were observed during February (0.075 per leat). June (0071 per leaf) and July (0074 per leaf). Highest number of whitefly per leaf was observed during the months of July-September, while lowest infestation was occurred during the cold months November-February. Infestation of aphids was built up during February to April (0137-0.278 per leaf). Peak infestation occurred (lIlting March (0278 per leaf). Positive correlation was observed in case of shoot and fruit infestation of BSFB and with temperature and rainfall. Warm temperature was favorable for the growth and development of jassid population, as there was positive correlation between jassid population with rise of temperature. But rainfall is detrimental for the jassid population growth. Population growth of whitefly was positively correlated with temperature and negatively correlated with rainfall. Epilachna adult population was positively correlated with temperature and negatively correlated with rainfall. Both temperature and rainfall have negative effect on the growth and development of aphid population. Aphids liked cool and dry temperature for its continuous growth and reproductive development.