Seasonal incidence of rice yellow stem borer, Scirpophaga incertulas (Walker) on different accessions in rice agro-ecosystem

摘要

Studies on population dynamics of yellow stem borer on different rice varieties revealed that the dead heart formation was observed from the 2nd week of August and peak deadheart formation was observed during 4th week of September in PS-15 (30.3%) followed by PR-113 (26.7%) and was minimum in HKR-4 (14.6%). The white ear head formation started from the 1st week of September and attained its peak during 2nd week of November with maximum white ears in NDR-359 (44.9%) followed by PR-113 (44.3%) and minimum in variety PS-5 (27%). White earhead symptom and weather parameters, showed that varieties, PR-113, HKR-47 and PS-15 exhibited significant negative correlation with maximum temperature. Significant negative correlation values -0.962, -0.927, -0.903,-0.931, -0.940 and -0.931 were recorded in varieties, PR-113, HKR-47, PS-4, NDR-359, Sarju-52 and PS-21, respectively with minimum temperature. Varieties PR-113, NDR-359, and Sarju-52 showed significant negative correlation with minimum relative humidity.