烟蚜传播云南烟草丛枝病研究

Investigation of the epidemic of tobacco witches broom carried by Myzus persicae (Homoptera:Aphididae)

由于烟草丛枝病在云南省的为害非常严重 ,本试验对该病的主要媒介害虫烟蚜的传毒特性进行了系列量化测定。从云南省大理、红河和昆明得到的烟草丛枝病每烟株 3头烟蚜成虫便可传毒 ,但当每烟株为 7头烟蚜成虫时传毒效率为3头时的 2倍 ,当每烟株上超过 10头烟蚜时其传毒效率达到最大。烟蚜的最短获毒时间为 15min ,而且传毒率随着获毒时间的增加而增加 ,当获毒时间达到 2 4h时传毒率最大。最短接种时间也为 15min ,其传毒率随着接种时间的增加而增加 ,超过 12h的接种时间使传毒率达到最大。对烟蚜进行不同获毒时间后的连续转移试验 ,无论获毒时间有多长 ,烟蚜成虫都要在开始获毒后的 2 4h才可传毒。所以 2 4h作为传毒时间阈值包括烟蚜开始获毒的时间和丛枝病病毒在烟蚜体内循回的潜育时间。

Because of the seriousness of tobacco witches broom in Yunnan Province, studies were conducted to quantify the characteristics of the phytoplasma of tobacco witches broom (PTWB) transmission by the Myzus persicae (Sulzer).Transmission of an isolate of the PTWB from Dali, Honghe and Kunming of Yunnan was achieved with three adults M. persicae, but the efficiency of transmission increased twofold when the number of adults were increased to seven per plant. It reached a maximum transmission efficiency when the number of adults were over 10 per plant. M.persicae transmitted PTWB after a minimum acquisition access period of 15 min, and rate of transmission increased as the acquisition access period was lengthened and reached a maximum after 24 h. A minimum inoculation access period of 15 min was observed with the rate of transmission increasing as the inoculation access period was lengthened,reaching a maximum after a 12 h inoculation access period. When M. persicae were transferred serially after acquisition, adults were unable to transmit PTWB until 24 h after the initiation of the acquisition access period regardless of the length of acquisition provided. The 24 h transmission threshold from initial vector access to a PTWB infected plant until transmission of the phytoplasma includes both the acquisition access period and the latent period during which the phytoplasma circulates within vector. Result of this experiment indicates multiplication of the phytoplasma in the vector.