Effect of NPK fertilizers on the incidence of shoot and fruit borer, (Leucinodes orbonalis Guen) in brinjal under insecticidal protection.
The effect of NPK fertilizers on the incidence of shoot and fruit borer, L. orbonalis was studied in separate experiments under protected conditions during kharif 1991 end 1992. at the Regional Research Station (O.U.A.T) Keonjhar, Orissa,India. In kharif 1991, application of 125 and 150% of the recommended dose of fertilizers (i.e. N:p2O5:K2O @ 125:80:100 kg/ha) recorded high fruit infestation (35.4-44.4%), while plots receiving no fertilizers showed minimum fruit infestation (26.1-27.6%). On the contrary, N at 125 kg/ha did not result in any perceptible variation in fruit damage (23.0-27.6%), irrespective of insecticidal application during kharif 1992. In addition, fruit damage did not vary with respect to levels of K (75 and 100 kg/ha) tested, during the same year. Irrespective of fertilizers, four sprays alternatively with endosulfan @ 0.5 kg kg a.i./ha and fenvalerate @ 0.1 kg a.i./ha recorded comparatively lower fruit damage both in quantity (21.7-37.6) and quality (20.1-35.3%) as against 25.5-46.5% infestation in untreated plots. Percent increase in yield however, was more due to fertilizer application (24.5-112.5) rather than insecticidal protection (10.8.-54.8).