Effect of climatic factors and agronomic practices on brown planthopper {Nilaparvata lugens) out-break in the Aeiiradhapura District, Sri Lanka

Abstract

Brown Plant Hopper (BPH) damage in rice was the major production constraint prevailed in 1997/98 South-West monsoon season in areas where the extent under rice cultivation was high. A survey was conducted during the later part of the same season to identify the causes for high BPH infestation in the Anuradhapura district. Of the severely damaged crop, 75% was found to be planted early and these crops had been in the ideal vegetative phase when the high temparature, which was at least four degrees higher than that of a normal South-West monsoon season and the humid micro-environment due to heavy rainfall had been the causes for rapid increase of BPH population. Indiscriminate use of insecticides and use of excessively high rates of nitrogen fertilizer as well as seed paddy had been the additional factors favourable for the BPH proliferation.