Influence of meteorological parameters on the incidence of leaf hopper in okra at Pusa, Bihar

Abstract

The effects of weather parameters on the incidence of leaf hopper (Amrasca biguttula biguttula) in okra were studied in Samastipur, Pusa, Bihar, India, during the summer of 2000 and 2001. Leaf hopper population densities of 34 and 27 per 30 leaves were recorded on the 10th standard meteorological week (SMW) when the ambient temperatures were 15.1-29.4 and 13.5-31.4°C in 2000 and 2001, respectively. The threshold pest density for the occurrence of epidemics was 2 leaf hoppers per leaf. The initial population at the 10th SMW started to increase progressively during the 13th to the 16th SMW, attaining the peak (229 and 216 leaf hoppers per 30 leaves) on the 16th SMW. Thereafter, the decline in pest population continued until the 17th-25th SMW (85 and 80 leaf hoppers per 30 leaves). Pooled data suggested that the pest build-up showed a highly significant positive correlation with the maximum temperature, and a high positive correlation with minimum temperature. Multiple regression analysis showed that a unit increase (1.0°C) in temperature will increase the number of leaf hoppers per 30 leaves by 9 in 2000 and 4 in 2001. The weather parameters accounted for 51.82% of the total variation in leaf hopper population.