PDF(Pubmed)
Abstract：
The whitefly, Bemisia tabaci (Gennadius), is a polyphagous and major pest of cotton worldwide. Both adults and nymphs of B. tabaci affect the crop by causing direct and indirect damage. A severe whitefly outbreak was experienced during 2015 on cotton in North India and this was followed by a profound infestation during 2022. The present research rigorously examined whether the proliferation in the whitefly population was an outbreak or the result of a multi factor resurgence. During 2015, whitefly counts remained above the economic threshold level (ETL) between 28th and 35th Standard Meteorological Week (SMW). However, during 2022 above ETL population was observed in 27th SMW and it persisted until 36th SMW. The peak incidence of the whitefly was noticed during 31st and 29th SMW in 2015 and 2022, respectively. The early pest build up in 2022 and longer persistence (≥10 weeks) over the cotton season resulted in more damage to cotton crop. Additionally, pest survillence across the zone on the farmers\' fields during 2022 revealed 44.4 per cent spots (585 out of 1,317 locations) above ETL while the corresponding locations in 2015 was 57% (620 out of 1,089). Thus, in 2022 infestation was not uniform in the entire zone wherein only few blocks of Punjab, Haryana and Rajasthan states of India experienced severe infestations of the whitefly. This study reports the complex of factors including weather, delayed sowing, use of tank mixtures/ subleathal doses of insecticides, pest resurgence etc. that might have possibly contributed to these upsurges in whitefly on cotton in north India.
摘要：
粉虱,烟粉虱（Gennadius），是全球棉花的多食性和主要害虫。烟草的成虫和若虫都通过引起直接和间接损害来影响作物。2015年，印度北部的棉花发生了严重的粉虱疫情，随后在2022年发生了严重的侵染。本研究严格检查了粉虱种群的增殖是爆发还是多因素复苏的结果。在2015年期间，粉虱数量在第28至第35个标准气象周（SMW）之间保持在经济阈值水平（ETL）以上。然而,在2022年期间，在第27个SMW中观察到超过ETL的人群，并持续到第36个SMW。粉虱的高峰发病率分别在2015年和2022年的第31和第29SMW期间出现。2022年的早期害虫积累和棉花季节的持续时间（≥10周）对棉花作物造成了更大的损害。此外,2022年期间，农民田地上的害虫蔓延显示，ETL上方有44.4％的地点（1,317个地点中的585个），而2015年的相应地点为57％（1,089个地点中的620个）。因此，2022年，整个地区的侵扰并不均匀，只有几个街区的旁遮普邦，印度的哈里亚纳邦和拉贾斯坦邦经历了粉虱的严重侵染。这项研究报告了复杂的因素，包括天气，延迟播种，使用坦克混合物/下剂量的杀虫剂，害虫死灰复燃等.这可能是印度北部棉花粉虱激增的原因。
