EFFECT OF PLANT EXTRACTS ON THE ACTIVITY OF THREE PAPAYA VIRUSES

Abstract

Crude leaf extract of Achyranthes aspera, Aloe barbadens, Capsicum frutescens and Carica papaya inhibit the activity of mild mosaic, distortion ringspot and ringspot viruses of papaya; Argemone mexicana and Carum copticum extracts inhibit the infectivity of DR and RS while Adenocalymna alliaceae is effective against MM only. Infectivity of all the three isolates was also inhibited by the seed extracts of Argemone mexicana, Datura fastuosa, Rhyncosia asnaris and Raphanus sativus. Seed extract of Rhyncosia asnaris which completely inhibited the infectivity of MM in vitro reduced its infectivity when sprayed on the leaves of host plants prior to inoculation or when applied as a soil drench. It was found to be stable against heat, dilution, ethyl alcohol and was partially dialysable. This seems to be of a complex nature having a protein and sugar as its components.