经传毒力测试，具有南方麦区代表性的长沙、南京和杭州的介体禾谷缢蚜，对小麦黄矮病（ＢＹＤＶ）的传播能力，同样不但赶上而且超过该病优势介体麦二岔蚜。这就预示随着我国南方麦区优势麦蚜种群禾谷缢蚜传毒力的显著提高，小麦黄矮病存在着由北方麦区往南方麦区扩展蔓延的趋势。 Through the test of virulence, the wheat Aphis gossypii, a mediator of Changsha, Nanjing and Hangzhou with typical southern wheat regions, also not only catches up with but also surpasses the dominant mediator of wheat disease, Aphis. This indicates that with the significant increase of virulence of Aphis gossypii in the southern wheat wheat aphid population in southern China, the trend of wheat yellow dwarf disease spreading and expanding from northern wheat to southern wheat.