Distribution and incidence of viral disease of black pepper (Piper nigrum L.) in Karnataka and Kerala, India

Abstract

Two hundred and seventy six plantations in 96 locations in major black pepper (Piper nigrum L.) growing areas of Kamataka and Kerala were surveyed for the distribution and incidence of viral disease. The incidence of the disease was highest in Wyanad District (45.4%) followed by Idukki District (29.4%) in Kerala. in Karnataka. Kodagu District ( 14.9%) had the highest incidence of the disease followed by Hassan District (5.2%). In general, the incidence and severity of (he disease was higher in black pepper plantations situated at higher altitudes of Kerala such as Idukki and Wyanad districts. Mosaic. reduction in leaf size and internode length leading to stunting of the vine. and bright yellow mottling along veins were the two foliar symptoms observed on diseased vines. DAC·ELlSA of symptomatic black pepper vines with antisera to different vi ruses confirmed viral infection either by CMV or BSV or by both. All cultivars and improved varieties including hybrids were susceptible to the disease under natural conditions. Vines of all ages raised on all kinds of standards were also found affected by the disease. Among the several weeds found in and around black pepper plantations. a few of them showed typical viral like symptoms, which might act as potential inoculum source. Though 12 species of insects were collected from diseased vines from different locations, no species was specifically associated with diseased vines