Evidence for transmission of aphid-pathogenic fungi by migratory flight of Myzus persicae alates

The alates of the green peach aphid, Myzus persicae, were daily trapped from the air from late October through early January and carried to laboratory for determination of fungal infection by individually rearing them for 7 d on detached cabbage leaves in Petri dishes. Among 760 alates trapped, 266 (35%) were found carrying various fungal pathogens, 87.3% of them died due to mycosis during the first 3-day period of rearing and the rest died in the following two days. Most of the deaths of the alates were attributed to entomophthoralean fungi, taking 94.4%, and the rest were the hyphomycetous fungus Beauveria bassiana. Among the Entomophthorales-killed alates, P. neoaphidis took a proportion of 66.1%, Z. anhuiensis 22.6%, E. planchoniana 9.7%, and N. fresenii 1.6%, respectively. Two alates were found suffering from cross infection of two fungal species, i.e. P. neoaphidis with Z. anhuiensis and N. fresenii, respectively. The results represent the first report on transmission of aphid-pathogenic fungi by M. persicae alates through migratory flight.     

黄瓜花叶病毒新疆株的桃蚜传播特性

研究了桃蚜传播黄瓜花叶病毒新疆株(CMV-XJ)的规律,结果表明：无毒蚜虫能够获毒的最短取食时间为30 s,获毒率随取食时间的延长而提高,取食时间为70 s以上时,获毒率达100%;带毒蚜虫传毒的最短取食时间为0.25 h,当取食时间超过最短传毒时间时,传毒率随取食时间的增加而升高,取食时间达2 h以上时,传毒率达100%;带毒蚜虫能够传毒的最少头数为1头,传毒率随单株植物带毒蚜虫数目的增加而升高,单株虫量达15头以上时,传毒率达100%.说明桃蚜可以高效率地传播黄瓜花叶病毒新疆株.     

烟蚜茧蜂对烟蚜在寄主烟叶上定位时间的影响

研究烟蚜被烟蚜茧蜂寄生前后,在寄主烟叶上的定位时间,结果显示,烟蚜茧蜂的寄生,对各龄烟蚜在烟叶上的定位时间无显著影响(P0.05)。当烟蚜数量固定为5头时,烟蚜在烟叶上的定位时间与烟蚜茧蜂的数量、蜂-蚜距离呈显著的正相关,且蜂-蚜距离对烟蚜定位烟叶的影响比烟蚜茧蜂数量对其影响更大。当烟蚜数量固定为2头时,烟蚜数量、蜂-蚜距离对该烟蚜定位时间影响不显著(P0.05),但在烟蚜数量和蜂-蚜距离双因素的作用下对烟蚜定位时间存在显著性影响(P0.05)。研究结果说明烟蚜在烟叶上的定位时间不受烟蚜茧蜂寄生与否的影响。虽然烟蚜茧蜂没有直接寄生烟蚜,但可能由于烟蚜受到烟蚜茧蜂气味、激素及视觉等间接影响,从而延长了烟蚜在寄主烟叶上的定位时间。因此,试验结果可为烟田利用烟蚜茧蜂防控烟蚜及是否要继续释放烟蚜茧蜂、放蜂量多少等问题提供科学参考。