Influence of Climatic Factors on Arthropod Pests and Associated Natural Enemies of Chilli (Capsicum annuum)

Abstract

Aims: To enabling conversant pest management decisions that balance pest suppression with ecological safety and economic viability. Place and Duration of Study: Department of Entomology, C. P. College of Agriculture, SDAU, Sardarkrushinagar in India during kharif-rabi, 2023-24 and 2024-25. Methodology: Total 25 plants were randomly selected to record the incidence of pest and their natural enemies at weekly interval starting from two weeks after transplanting till crop period. Results: During kharif-rabi, 2023-24 and 2024-25, seasonal incidence of sucking pests and their natural enemies on chilli crop was studied. The results revealed that thrips population reached to peak on 47th SMW and 46th SMW with 8.72 and 7.84 thrips/leaf, respectively. Thrips abundance showed non-significant positive association with maximum temperature (r=0.215 and 0.223) while negative with minimum temperature (r=-0.036 and -0.035), respectively. Whereas, evening relative humidity (r=0.587** and -0.574*) showed significant positive and negative correlation, respectively. The multiple regression analyses showed 75.10 and 82.0 per cent variation of thrips population due to the influence of all abiotic factors. However, the mite population reached at peak in 50th and 49th SMW with 2.64 and 2.48 mite/cm2 leaf during the year, 2023-24 and 2024-25, respectively. It displayed a highly significant negative association with maximum temperature (r=-0.790** and -0.757**) and minimum temperature (r=-0.806** and -0.872**) while a non-significant negative correlation with morning relative humidity (r=-0.194 and -0.197), respectively. Abiotic factors contributed 95.8 and 88.0 per cent (R2 = 0.958 and 0.880) of total variation in the of mite population. The population of spider reached maximum in 52nd SMW and 1st SMW with 5.96 and 5.12 spiders/plant, respectively. Spider population exhibited negative and non-significant correlation with bright sunshine hours (r=-0.259 and -0.393) and morning relative humidity (r=-0.331 and -0.062), respectively while, highly significant and negative with maximum temperature (r=-0.797** and -0.901**) and minimum temperature (r=-0.823** and -0.852**), respectively. Regression analysis indicated 92.9 and 88.8 per cent variation of spider population due to the influence of all abiotic factors. Coccinellids reached to its peak on 1st SMW and 52nd SMW with 2.04 and 1.88 coccinellid per plant, respectively. Coccinellid populations had a highly significant negative association with maximum temperature (r=-0.878** and -0.864**) and minimum temperature (r=-0.940** and -0.865**), respectively. Whereas, morning relative humidity showed significant and non-significant negative correlation with (r=-0.425* and -0.092), respectively. A total of 95.8 and 88.0 per cent (R2 = 0.949 and 0.905) variation in the abundance of coccinellid was observed due to contribution of weather parameters.