Temporal dynamics of sucking pest and field response of promising insecticidal molecules in okra

Abstract

To investigate the response due to application of newer insecticide on sucking pest in okra, a trial was designed at field level for three consecutive years from 2011-12 to 2013-14 in kharif season. Moreover, impacts of applied insecticides on natural enemies were also assessed. Based on experimental finding thiamethoxam 25WG 0.003% (2.83 per 3 leaves, 0.93 per 3 leaves), imidacloprid 70WG 0.004% (3.49 per 3 leaves, 1.30 per 3 leaves) and thiacloprid 21.7 SC 0.006% (4.28 per 3 leaves, 1.75 per 3 leaves) provided superior control of leafhoppers and whiteflies population on okra. Effectiveness of these treatments was reflected in terms of reduction in population of both insects and significantly increases (thiamethoxam: 95.50 q/ha, imidacloprid: 86.96 q/ha and thiacloprid: 80.99 q/ha) the fruit yield in comparison to others. However, the incidence of Yellow Vein Mosaic disease was recorded least in thiamethoxam 0.003% sprayed plots followed by imidacloprid 0.004%. Slow progress in the population of
whitefly and leaf hopper was recorded in thiamethoxam 0.003% applied plots. There was positive correlation between whitefly and virus incidence in conducted field trial. Under the experiment, neonicotinoids group of insecticides have not adverse effect on natural enemies in okra crop. The information generated under the study can be incorporated in management modules in crop okra without disturbing the ecology of natural enemy and cropping system. In our findings, the quantitative data of temporal increment of whiteflies and mosaic disease will be helpful in understanding or formulating of epidemiological models.