Int.J.Curr.Microbiol.App.Sci (2019) 8(4): 752-756 752 Original Research Article https://doi.org/10.20546/ijcmas.2019.804.082 Seasonal Incidence of Insect-pests of Soybean and their Correlation with Abiotic Factors Nikki Bhardwaj 1* , Bhavna Verma 2 and Praveen Bhardwaj 1 1 Jagannath University, Jaipur (Raj), India 2 Dr. B.R. Ambedkar University of Social Science, Mhow (MP), India *Corresponding author ABSTRACT Introduction Soybean (Glycine max (L.) Merril) is known as the “Golden Bean” of the twentieth century. It has emerged as an important commercial crop in many countries and international trade of soybean is spread globally. Though soybean is a legume crop, yet it is widely used as oilseed. It can be grown on a variety of soil and in a wide range of climate. Soybean is a kharif crop in India, sown in June-July and harvested in late September–October. Nationally soybean occupies an area of 108.39 lakh ha and its production is 114.83 lakh MT. Madhya Pradesh ranks first in total area (54.09 lakh ha and 51.50%) and International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 8 Number 04 (2019) Journal homepage: http://www.ijcmas.com A field experiment was conducted during kharif crop season 2015-16 at college of agriculture, Indore (M.P.) on cultivar RVS 2001-4 to assess the effect of weather factors on the trend of blue beetle and tobacco caterpillar activities. The crop was sown in second week of June, 2015-16 in an area of 200 (20x10m) square meters following the recommended agronomical practices with the spacing of 40 x10 cm rows and plants, respectively. The observations on the appearance of major insect pests were recorded from germination to harvest of the crop at weekly intervals at 10 different sites in 1 meter row length from each site once in a week and correlation was worked out. For blue beetle per cent infestation and for tobacco caterpillar, larval population was counted. Blue beetle infestation started in 26 th MSW with 1.3% damage. The infestation increased and reached its peak as 7.5 % in 32 th SMW ending 31 th August. After that the infestation decreased slowly in next two weeks and noted least as 3.1% in 33 th SMW ending 7 th September. The occurrence of tobacco caterpillar started with 2.5% insects in 29 th SMW ending 10 th august. The population fluctuated and reached its peak as 14.5% in 35 th SMW ending 21 st September. Both the insects significant negative correlation with maximum temperature (blue beetle, r = -0.667 and tobacco caterpillar, r = -0.528). Blue beetle significant positive correlation with rain fall and rainy day (Rainfall r = 0.572 and Rainy day, r= 0.572) and tobacco caterpillar significant positive correlation with morning humidity was recorded. Rest of the abiotic factors exhibited non significant positive or negative correlation for both insects. Keywords Weather factors, blue beetle, Tobacco caterpillar and Correlation and regression Accepted: 07 March 2019 Available Online: 10 April 2019 Article Info