WHITEFLY (Aleurolobus barodensis Mask.) SPATIO-TEMPORAL TRENDS IN SEMI-ARID AGRO-ECOLOGICAL ZONES OF PAKISTAN

Three farmer’s fields of sugarcane of 10-15 kilometer (km) radius in environs of layyah sugar mills, layyah (lsl), sheikhoo sugar mills, muzaffargarh (ssm) and indus sugar mills, rajan pur (isr) were selected to evaluate the fluctuation in whitefly population. the data were recorded at fortnight interval during the crop season in 2008 and 2009 from april to december by randomly selected twenty leaves from each field of one hectare at each locality. the data were correlated with the ambient weather factors (temperature, humidity and rainfall). the population of whitefly (nymph and adult) varied significantly (p≤0.05) among observation interval and localities. the whitefly appeared during second fortnight of june in district lsl and isr, while in district isr it was appeared during first fortnight of july. the maximum mean population was recorded on first fortnight of november in district lsl (7.96/leaf) and isr (14.94/leaf), while on second fortnight of october in district ssm (15.81/leaf). the isr showed maximum whitefly population (4.61/leaf), while district lsl furnished lower population (2.48/leaf). it was found that the relative humidity had positive and significant (p≤0.05) correlation with the whitefly population and it contributed 42.3%, 43.8% and 35.9% in lsl, ssm and isr district, respectively and the trend of whitefly appearance was found similar in 2008 and 2009. the relative humidity played positive and significant role for population fluctuation during the month of october and november.