Succession and Incidence of Major Sucking Insect Pests of Cowpea and their Natural Enemies in Relation to Meteorological Parameters

Abstract

Aims: To correlate population of major sucking insect pests on cowpea with the predator and abiotic factors. Study Design: Five separate plots of 3.0 m x 2.5 m size keeping row to row and plant to plant distance of 30 cm and 10 cm, respectively were maintained. Place and Duration of Study: The investigations were carried out in Kharif, 2022 at Agronomy farm, Shri Karan Narendra College of Agriculture, Jobner. Methodology: The RC-19 variety of cowpea was sown on 14th July, 2022 and the recommended agronomic package of practices was adopted for raising the crop excluding plant protection measures. The observations on insect pest populations (aphid, leafhopper, and whitefly) were recorded on five randomly selected and tagged plants in each plot at a weekly interval and simple correlation was computed between mean observations of pest populations, natural enemies and meteorological parameters. Results: The infestation of the aphid commenced in the first week of August (31st SMW) and leafhopper and whitefly in the last week of July (30th SMW). The peak populations of aphid (111.68 aphids/ 10 cm terminal shoot), leafhopper (13.20/ three leaves) and whitefly (8.80/ three leaves) were recorded in the first week of September (35th SMW), when the minimum temperature, maximum temperature and relative humidity was 21.10C, 33.20C and 41 per cent, respectively. The leafhopper and whitefly showed significant negative correlation with relative humidity (r= -0.67 & -0.68) and a non-significant correlation with other meteorological parameters. The population of aphid and Coccinella septempunctata showed non-significant correlation with all the meteorological parameters, whereas, the population of Coccinella septempunctata showed positive significant correlation with aphid (r= 0.88), leafhopper (r= 0.87) and whitefly (r= 0.82) population. Conclusion: Populations of leafhopper and whitefly showed a significant negative correlation with relative humidity and Coccinella septempunctata showed a positive significant correlation with the populations of aphid, leafhopper and whitefly. The conclusion of the study is that the populations of insect pests depend on the biotic and abiotic factors of environment and by analysing the environmental conditions, the incidence of insect pests can be predicted so that timely management practices can be applied.