Seasonal incidence of major pests of cabbage and their natural enemies

The cabbage crop was found to be infested by two major pests i.e., aphid (Lipaphis erysimi (Kalt.)) and diamondback moth (Plutella xylostella (L.)). The infestation of L. erysimi started in the last week of November and reached peak in third and fourth week of January during Rabi 2008–09 and 2009–10, respectively. Whereas, the infestation of diamondback moth started from the third week of November and reached peak in the first week of January. The maximum and minimum temperatures showed significant negative correlation with aphid and larval population of diamondback moth, whereas, relative humidity and sunshine hours showed non-significant correlation. The coccinellid beetle was recorded as a important predator of aphid, which was maximum in the second and third week of January during 2008–09 and 2009–10, respectively.