Cairo University, Faculty of Agriculture, Department of Economic Entomology and Pesticides, Cairo, Egypt.
Braz J Biol. 2021 Dec 1;84:e246460. doi: 10.1590/1519-6984.246460. eCollection 2021.
Field survey study was conducted season (2017). Soybeans and weeds were weekly sampled randomly. Thrips adults were identified and counted. Detection of the virus isolate and the natural incidence was determined using; Mechanical transmission, host range, DAS-ELISA, RT-PCR. The natural incidence thrips individuals was detected depending on the SVNV% in thrips individuals and weeds hosts. Ten thrips species were associated with soybean plants in the field. The most abundant species was T. tabaci, average 256.5 average no.of individuals, followed by F. occidentalis (142.5 average no. of individuals), then N. variabilis (86.6/ average no. of individuals). Fourteen thrips species occurred on 5 legumes field crops and 41 weed plant species within soybean field. The highest average number 40.6.of individuals were recorded on Ammi majus. While the lowest one 3.3 average no. of individuals were on Urtica urens. Only 21diagnostic plant species were susceptible to infection with SVNV. G. max and Vigna radiate, were the highest percentage of infection 80% followed by V. unguilata & N. benthamiana, 75%. Egyptian isolate of Soybean vein necrosis virus (SVNV) in this study showed a high degree of similarity and it is closely related to TSWV from Egypt (DQ479968) and TCSV from USA (KY820965) with nucleotide sequence identity of 78%. Four thrips species transmitted SVNV (F. fusca 4.0%, F. schultzei 4.3%, F. tritici 3.3% and N. variabilis 68.0% transmission). Both C. phaseoli and M. sjostedti can acquire the virus but unable to transmit it. The following species; T. tabaci, F. occidentalis, S. dorsallis and T. palmi cannot acquire or transmit SVNV. The incidence of SVNV in the field started by the end of July then increased gradualy from 12.7 to 71.3% by the end of the season. In conclusion, few thrips individuals invaded soybean crops are enough to transmit high rate of SVNV within the crop. Furthermore, several vector species are also abundant on weeds, which are the major sources of soybean viruses transmitted to the crops. This information might be important for control and reduce the incidence of SVNV infection.
本研究于 2017 年进行了田间调查。每周随机抽取大豆和杂草样本。鉴定并计数蓟马成虫。采用机械传播、寄主范围、DAS-ELISA、RT-PCR 检测病毒分离物和自然发病率。根据蓟马个体和杂草寄主中的 SVNV%检测自然发生的蓟马个体。在田间与大豆植株相关的有 10 种蓟马。最丰富的物种是 T. tabaci，平均 256.5 个个体，其次是 F. occidentalis（平均 142.5 个个体），然后是 N. variabilis（平均 86.6/个个体）。在 5 种豆科作物和大豆田内的 41 种杂草植物中发现了 14 种蓟马。在 Ammi majus 上记录的个体平均数量最高为 40.6。而在 Urtica urens 上记录的个体平均数量最低为 3.3。只有 21 种诊断植物物种易感染 SVNV。G. max 和 Vigna radiate 的感染率最高，为 80%，其次是 V. unguilata 和 N. benthamiana，为 75%。本研究中的埃及大豆叶脉坏死病毒（SVNV）分离株与埃及的 TSWV（DQ479968）和美国的 TCSV（KY820965）具有高度相似性，核苷酸序列同一性为 78%。4 种蓟马（F. fusca 4.0%、F. schultzei 4.3%、F. tritici 3.3%和 N. variabilis 68.0%）传播 SVNV。C. phaseoli 和 M. sjostedti 均可获得病毒，但不能传播。以下物种；T. tabaci、F. occidentalis、S. dorsallis 和 T. palmi 不能获得或传播 SVNV。SVNV 的田间发病率从 7 月底开始，到本季末逐渐从 12.7%增加到 71.3%。总之，入侵大豆作物的少量蓟马个体足以在作物内传播高比例的 SVNV。此外，几种传毒物种在杂草上也很丰富，它们是传播到作物的大豆病毒的主要来源。这些信息可能对控制和减少 SVNV 感染的发病率很重要。
