PROGRESS OF PEPPER VENOUS MOTTLE VIRUS-DISEASE IN CAPSICUM PEPPERS

The primary source of pepper veinal mottle virus (PVMV) in pepper plots was not known, although tobacco plants growing within a 500 m radius from plots were positive for PVMV in ELISA, whereas other cultivated and wild hosts were negative. Three aphid species known to transmit PVMV (Aphis gossypii, A. spiraecola and A. craccivora) were trapped in the plots. The aphid population was generally low, but A. craccivora was predominant in terms of numbers trapped. As apterous aphids were not found crawling from plant to plant, only alate aphids were implicated in primary and secondary infections. The logistic model fitted the disease progress data satisfactorily as the coefficients of determination were high in all cases. Virus infection rates (r) varied in the six pepper lines, with lines CO 1 263 and CO 1 294 being comparatively more resistant because of their lower slope values (r = 0.04). In addition, line CO 1 263 possessed vertical resistance against PVMV, as it delayed the start of the epidemics. Disease progress curves can be used to identify varieties with field resistance.