Population dynamics of insect pests of coriander and their correlation with biotic and abiotic factors

Abstract

Population dynamics of insect pests of coriander and their correlation with biotic and abiotic factors were studied in the department of Entomology, S.K.N. College of Agriculture, Jobner (Sri Karan Narendra agricultural University, Jobner) during two consecutive years i.e., rabi, 2015-16 and 2016-17. The coriander crop has been found to be infested by aphid, Hyadaphis coriandri (Das), whitefly, Bemisia tabaci (Gennadius), thrips, Thrips tabaci (Lindeman) and mite, Petrobia latens (Muller), among these, the coriander aphid was reported as a regular and major pest. The infestation of aphid was started from second week of January on early and third week of January on normal and late maturing varieties and peaked in the fourth week of February on all three varieties in both the years. The peak activity of aphid on all three varieties was observed at 30.1-32.7 0C maximum and 9.7-12.1 0C minimum temperature with average relative humidity between 51.0-54.5 percent during both the years. The maximum temperature had significant effect on aphid population, whereas, minimum temperature, average relative humidity and rainfall had non-significant effect. Among the natural enemies, coccinellids predator have been found preying aphid, H. coriandri on the coriander crop in both the years. The peak activity of coccinellids coincided with the peak infestation of aphid. The correlation metrix studies between the aphid, H. coriandri and the coccinellids predator depicted significant positive correlation in both the years. The maximum and minimum temperatures, average relative humidity and rainfall had non-significant effect on the coccinellid predators.