Sasidharan Pillai, KSrinath, BKAU2019-02-132019-02-131990170269http://krishikosh.egranth.ac.in/handle/1/5810094887PGWater extracts of eight locally available plants of known insect control potential were screened at 2 and 4 per cent concentrations against pests of amaranthus and bhindi in a pot culture experiment in comparison with carbaryl and tobacco decoction. T. nerifolia followed by A. indica, C. infortunatum and E. odoratum were highly effective against P. basalis on amaranthus and A. gossypii on bhindi. C. infortunatum and T. nerifolia followed by A. indica, N. oleander and E. odoratum were effective against A. biquttula biguttula. T. nerifolia and A. indica followed C. infortunatum and E. odoratum reduced damage caused by E. vittella. Carbaryl 0.2 per cent was superior to plant extracts and tobacco decotion was effective only against aphids. A laboratory study was undertaken for augmenting the toxicity of five aqueous plant extracts by adding with teepol, soap and coconut oil at varying concentrations and combinations. Toxicity of eight and four per cent extracts of C. infortunatum and eight per cent extract of T. nerifolia with teepol, coconut oil and soap reduced the adult emergence of S. litura. A. indica and T. nerifolia were more effective against A. gossypii when the extracts were mixed with soapwater. Teepol and coconut oil also had the same effect with eight per cent T. nerifolia. Field experiment was conducted with the extracts of A. indica, T. nerifolia and C. infortunatum at two and four per cent concentrations without and with soap against pests of amaranthus and bhindi using carbaryl and tobacco decoction as standards. Carbaryl was superior to plant extracts in controlling the population of pests. Four per cent extracts of A. indica, two and four per cent extracts of T. nerifolia and C. infortunatum protected amaranthus against A. crenulata and P. basalis. Toxicity of the extracts A. indica and T. nerifolia was augmented with soap at lower concentration. All the plant extracts increased the crop yield but lesser then carbaryl. Tobaco decoctin failed to control the pests incidence and to increase the yield. Two and four per cent extracts of T. nerifolia caused heavy mortality of A. gossypii. Four per cent extract of A. indica was more effective than carbaryl followed by C. infortunatum, and T. nerifolia against A. crenulata on bhindi. C. infortunatum with soap was efficient against A. biguttula biguttula. Four per cent extracts of T. nerifolia and A. indica were highly effective against E. vitella. T. nerifolia four per cent was effective against S. derogate. Plant extracts were not toxic as carbaryl to C. sexmaculata. All the plant extracts other than at 2 per cent concentration increased the yield and T. nerifolia recorded maximum, but lesser than carbaryl. Tobacco decoctin had no impact on yield. Toxicity of 2 per cent extract of T. nerifolia was augmented with soap against pests of bhindi.ennullThesis