Influence of meteorological parameters on the jassid infestation on cotton at Akola

Abstract

Key words-Meteorological parameters. Jassid populauon. Cotton, Pest WeatherCalendar. ABSTRAl.•. Influence of different metcorologic.aJ parameters un jassid (Amrnscu b'K"lluln bigUltllla Ishida) populati on on cOllon at Akola. Maharashtra was studied wilh 14 yearsdata from 1979 to 1992. Jassid remained active from last week of July lill second week of October in the years under study. Fall in afternoon and morning relati ve bumidines respectively at 32nd and :Hlh wed: and increase in minimum temperature at 36th week favoured pest development. Cloudy weather al 39th week also Increasedjass id population after two wee ks. Minimum temperature ~ 22.4'"C at 361h week. was found10 be themost predominant weatherparameter influencing sudden increase injassid infestation. Jassid weather calendar of cotton could be used forear lywarning purposes in theAl oia region. llR-'ImTI: <941 (l:('Im l\ ~ iPT ~ "11 lI'IXlI %1 2. Data and methodology The quantitative pest da ta for j assid for 14 years (1979-92) were co llected fro m the Department of En tomology, Punja brao Krishi Vidyapeeth, Akola (24 0 42'N, 77 0 02'E). Ob servations ofjassid on cotton were recorded in one block in the ex pe rimental pl ot of the University which was kept undernature: i conditions forrecordingobservationsof jassid infestation. No insecticide was applied in the control experi-menta l plo t throughout the cro p gro wi ng period. The observat ions were recorded at weekly interval on plant s, randomly selec ted in block. Th ree leav es pe r plant were selected from the top. n i MIc and lowcr portion forthc pest observation. The daily meteorological par amete rs-possib le throu gh the knowl ed ge of existing inter-rel aionsh ip between jassid po pulation and favou rable mete orological parameters. Keeping in view the above facts, an attempt has been made in this paper to inve stig ate the relationship be-tweenjassid population and a few meteorological elements. like weekly total rainfall, mean maximum and minimum temperatures, mean rel ative humidity (both morning and afternoon) and mean sunshine hours. (507) I. In trod u ction Jassid is one of the destru ctive pests in the cotton-pest complex. It is widely distributed in Ind ia and causes more damages to con on crop in the northwestern region. Owing 10 the incide nce o fja ssid, plan ts 10>