Ecology, Environment and Conservation Paper

Vol 29, Issue 1, 2023; Page No.(381-387)

INCREASED EFFICACY OF ENTOMOPATHOGENIC FUNGUS,BEAUVERIA BASSIANA (BALSAMO) VUILLEMIN(ASCOMYCOTA: HYPOCREALES) AGAINST LEAF FOLDER,CNAPHALOCROCISMEDINALISGUENEE (LEPIDOPTERA:PYRALIDAE), INCIDENCE ON SILICA ENRICHED RICE CROP

I. Paramasiva, T. Murali Krishna, Ch. Sreelaksmi, U. Vineetha and P. Madhusudan

Abstract

A possible synergistic effect between biological control agent Beauveria bassiana (Bb) and potassium silicate(K2Sio) for control of leaf folder on rice was investigated at Agricultural Research Station, Nellore (ANGRAU,Guntur, Andhra Pradesh) under field conditions. Three sequential Silicon application in theform ofpotassium silicate (KSil) was given as foliar spray @ 80 mg/l, when leaf folder population density reachedto ETL, B. bassiana @ 1.3x106 conidia/ml application was carried out. Two sequential applications ofpotassium silicate (two weeks after transplantation and at active tillering stage) + B. bassiana caused leaffolder population reduction of 42.80 per cent over control at 8 days after spraying. This reduction wassignificantly higher than the mortalities caused by the two single treatments alone (B. bassiana: 17.55 %; Ksil@ 2sprayes: 8.83). This study providing strong evidence of a synergistic effect of the combination treatmenton leaf folder mortality. Similarly, three sequential applications of potassium silicate (two weeks aftertransplantation, at active tillering stage and PI stage) + B. bassiana caused 41.88 % reduction in leaf olderpopulation over control at 8 days after spraying, whereas three sequential applications of potassium silicateand application of B. bassiana alone caused 20.57 and 17.55 % reduction in leaf folder incidence, respectively.Indicates application of potassium silicate and B. bassiana alone did not gave as satisfactory results as usedin combinations. In the present study the sequential applications of Potassium silicate + B.bassiana gavemore promising control of rice leaf folder compared to the application of B. bassiana alone, proving thesynergistic effect of the potassium silicate + B. bassiana combination on leaf folder incidence.