Abiotic factors influencing the occurrence of natural enemies associated with major insect pests of cauliflower

The incidence of all the natural enemies commenced during December and January months. Aphidiphagous parasitoids and syrphids reached their peak population of 54.10 and 73.83 mummified aphids/plant; and 2.23 and 2.30 maggots/plant, respectively in February during both the years of study, while the maximum population of predatory coccinellids and spiders appeared in March, reaching a peak population of 2.53 and 2.63 beetles/plant; and 0.30 and 0.23 spiders/plant during the two consecutive seasons of the experiment, respectively. Their occurrence was in positive correlation with atmospheric temperature, wind velocity and sunshine hours; and in negative correlation with relative humidity and rainfall, during both the years. Also, the relationship of aphid with its natural enemies viz., Diaeretiella rapae (parasitoid), predatory coccinellids and syrphids was noticed to be significantly positive with correlation coefficient (r) values ranging from 0.80 to 0.97 during both the years of study.