Considering sowing dates and host crop affects population incidence of whitefly in greengram and blackgram, the present study was undertaken with four different dates of sowing at 10-day interval: 24 July, 3 August, 13 August and 23 August 2019 with two varieties of greengram (IPM 205-7 & DGGV 2) and one variety of blackgram (IPU 94-1). Whitefly population varied significantly amongst the crops sown on different dates. Delay in sowing by 10 days (24 July–3 August), significantly increased the number of whiteflies from 3.68 to 4.52 adults per plant in IPM 205-7 (greengram), 7.38–14.52 adults per plant in DGGV-2 (greengram) and 28.46–31.7 adults per plant in IPU 94-1 (blackgram). Peak population was observed in the 36th Standard Meteorological Week (3–9 September) and started declining thereafter. Preference of whitefly towards varieties studied was in the order of IPU 94-1 (blackgram) > DGGV-2 (greengram) > IPM 205-7 (greengram).

考虑到播种日期和寄主作物会影响绿豆和黑豆中粉虱的种群发生率，本研究以10天间隔的四种不同播种日期进行：2019年7月24日，8月3日，8月13日和8月23日，两种绿豆（IPM 205-7和DGGV 2）和一种黑字（IPU 94-1）。在不同日期播种的农作物中，粉虱种群差异很大。播种推迟10天（7月24日至8月3日），在IPM 205-7（绿皮草）中每株植物的粉虱成虫数量从3.68增加到4.52，在DGGV-2（绿皮草）中每株植物的粉虱成虫数量从7.38-14.52增加， IPU 94-1中每株植物的成虫成虫为28.46–31.7个（黑克）。在第36个标准气象周（9月3日至9日）观察到人口高峰，此后开始下降。