Insect Pests Dynamics and Their Weather-based Population Fluctuation in Mungbean Crop in Hot Arid Region of Western Rajasthan

Background: Mungbean is one of the important major pulse crops of the country. The Indira Gandhi Canal and groundwater irrigation have brought about significant ecological changes in the hot, dry region. Crop patterns have drastically shifted due to the availability of water for irrigation. Since the insects are, poikilothermic creatures, also prone to climate change. Therefore, it aimed to study the insect pest scenario in changing crop and climate of this region. Methods: Survey and surveillance was done at fortnightly intervals. A total of 10 locations of mungbean were selected in Jaisalmer covering distance about 100-120 km while each filed/village had a distance of 5-7 km. Fixed plot survey approach was adopted and observations were taken at fortnightly interval from five spots in a field. From each spot, 3 plants were randomly examined. Weather data recorded at agro-meteorology unit of experimental area chandan (located 40 km from Jaisalmer) of regional research station Jaisalmer of ICAR-Central Arid Zone Research Institute was used for the study. Result: Insects i.e., Spotted pod borer, pod borer, blister beetle, looper, sphinx moth caterpillar, leaf folder, whitefly, thrips, leaf miner were found on mungbean, of these major were thrips, pod borer and spotted pod borer. Blister beetle was also observed as voracious and devastating but sporadic. Shannon’s diversity index recorded in this study was 1.45 altogether. Spotted pod borer and American pod borer appeared in second fortnight of July (0.05 and 0.06 larvae) and reached to peak (1.02 and 1.01 larvae) in first fortnight of Sept. Thrips seen (0.51 thrips) in second fortnight of July and maximum (4.3 thrips) in first fortnight of September. Mean maximum temperature exhibited mild effect on the decrease of spotted pod borer and increase of Helicoverpa and thrips population while minimum had moderate effect. Mean Maximum and minimum Relative humidity demonstrated strong significant positive effect.