Influence of weather parameters on incidence of yellow vein mosaic virus in okra

Investigation was undertaken to find out influence of different weather parameters on incidence of YVMV disease in okra. Twelve okra genotypes were sown in randomized block design with three replications accommodating sixty plants of each genotype during rainy season of years 2007, 2008 and 2009. Incidence of YVMV disease was recorded at 30, 60 and 90 days after sowing in each genotype. Pooled data on per cent incidence of YVMV was subjected to correlation and regression analysis. Per cent incidence of YVMV disease was higher in 90 days old crop followed by 60 and 30 days old crops. Bright sunshine hours showed significantly positive association (r = 0.94**) and minimum temperature showed significantly negative correlation (r=-0.89**) with YVMV disease incidence. Morning relative humidity expressed positive correlation (r = 0.14) whereas, evening relative humidity expressed negative correlation (r = -0.61) with the disease incidence. All weather parameter except minimum temperature (78%) and bright sunshine hours (84%) expressed poor potential (below 2.0%) for the spread of the disease. However, when these parameters were taken together in the form of multiple regression equation, prediction potential was improved to the tune of 98%. Thus, most of the weather parameter in combination influenced the incidence of this disease. However, bright sunshine hours (9.0 ± 0.5 hrs) coupled with low night temperature (21.5 ± 20C) played important role for the spread of YVMV disease in okra.