Influence of Abiotic Factors on the Population of Dysdercus koenigii Fab. (Hemiptera: Pyrrhocoridae) in Cotton Field in Pakistan

Four different genotypes of cotton NIAB–98, FH–1000, MNH–636 and Sohni were tested during this study. The objective of this study was to see the impact of abiotic factors that is field temperature and relative humidity on population dynamics of red cotton bug, Dysdercus koenigii Fab. on different varieties of cotton under unsprayed field conditions of the Nuclear Institute for Agriculture and Biology (NIAB), Faisalabad city of Pakistan. Population fluctuation of D. koenigii, fluctuated rates of field temperature and relative humidity were monitored after each interval. The results of the field study revealed that the bug population was found throughout the crop season from July to October 2003. The highest survival percentage of bug (19.23%) was observed during 1st week of September when the temperature and relative humidity were recorded 31˚C and 64%, respectively. While the lowest population of insect pest (4.15%) has been found during 3rd week of October when the temperature was 24˚C and relative humidity was recorded as 59%. Overall infestation of D. koenigii was 18.30±1.05, 17.00±0.24, 16.60±2.72 and 15.00±0.38 per three leaves on FH–1000, NIAB–98, Sohni and MNH–636 variety of cotton, respectively. Consequently, it was justified that the resistant genotype of cotton against the infestation of D. koenigii in relation to field temperature and relative humidity is MNH–636 while the highly affected is FH–1000.