~a5ttr of ~[irnrr In ~grl(ulturt

Transcription

1 COMPATIBiliTY OF CERTAIN FUNGICIDES AND INSECTICIDES USED FOR THE CONTROL OF MAJOR DISEASES AND INSECT PESTS INFESTING THE RICE CROP By G37 KALPANA, T. A. -'/ j o' f0~ 41 (..)( THESIS a ~ \Inu~'~ r~a. U 1 ). \ ) Submitted in partial fulfilment of the \ 'it\",./ J \ ~.t requirement for the degree ~, ~n ~- t"'v ~a5ttr of ~[irnrr In ~grl(ulturt Faculty of Agriculture Kerala Agricultural University Department of Plant Pathology COLLEGE OF HORTICULTURE Vellanikkara THRISSUR 1992

2 # CERTIFICATE Certified that this thesis enti tled "Compatibility of certain fungicides and insecticides used for the control of major diseases and insect pests infesting the rice crop"is a record of research work done independently by Miss.Kalpana, T.A. under my guidance and supervision and that it has not previously formed the basis for the award of any degree, fellowship or associateship to her. Vellanikkara, \ fr~ Dr. SALLY K. MATHEW Chairperson. Adv isory Committee Associate Professor of Plant Pathology

3 ABS~'\CT The efficacy of four fungicides and four insec~i~tdes alone and in combina,tion were studied at diff8rent concentrations (RecommeI1ded, three-fourth and half the recommended concentrations) against two major diseases of ~ice 113.mely, rice blast caused by?yricularia oryzae Cavar:..Laad sheath blight caused by R~dzoc..':;..onia solani Kuhn. arld two major insect-pests namely, leaffolder C'.1aphalocrocis medl'.1ali!!guen. and brown planthopper Nilaparvatha lugens Stale at tillering, panicle ini tia tion and flowering stages of the crop. The -- experiment was' conducted in vivo and in vitro conditions during 1989-'91, at the College of Horticulture, Vellanikkara. Thrissur. In general, combined application of fungicides and insecticides controlled the diseases and insect'-pests more effectively than the treatments given separately. At tillering stage, a synergistic effect of fungicide was observed, when it was sprayed along with insecticidee. Among different combinations tried, tridemorph (0.1 per cent).-, t + monocrotophos (0.0375%) and carbendaz.:.m CO.075%) -:.quinalphos (0.025 per cent) were the best combinations'against blast and sheath blight respectively. In t.he case of leaf folder and

4 brown planthopper, quinalphos was found to be the best insecticide, when used alone and also in cornbina tion with fungicides.. At panicle initiation stage, combined sprays of higher concentrations of carbendazim and monocrotophos was the best combination in controlling both g. solani and ~. lug~. But ediphenphos-phosphamidon combination was found to be the superior against~. lugens. When combined spraying was given at flowering stage, captafol (0.225 per cent) + quinalphos ( per cent) and carbendazim (0.075 per cent) + monocrotophos ( per cent) were found to be the best combinations against f. oryzae and R. solani respectively. But, c~rnbination of recommended doses of quinalphos with t~~demorph and ediphenphos and, phosalone with ediphenphos were the effective treatments in controlling \, c. medinalis and~. lugens respectively. '-- In in vitro studies, a total inhibi ti<;m of the test organisms, viz. f. Q~yzae and R. solani were observed in all the treatments. Whereas, in the case of c. medinalis recommended doses of quinalphos in combination with ediphenphos and carbendazim and phosalone with tridemorph recorded highest mortality; while, highest dose of quinalphos with captafol and phosalone with ediphenphos were the superior combinationsagainst~. lugens.

5 From the above findings it could be concluded that, the fungicides viz. ediphenphos, carbendazim, captafol and tridemorph are compatible with all the four insecticides tried viz., Phosphamidon, quinalphos, phosalone and monocrotophos in controlling the diseases, blast and sheath blight and insect pests leaffolder and brown planthopper.