黑尾大葉蟬 (Bothrogonia ferruginea) 生活史及媒介葡萄皮爾斯病之傳播效率探討

Abstract

Pierce’s disease (PD) of grapevines caused by a xylem-limited bacterium, Xylella fastidiosa (Wells, 1987) is one of the plant diseases under international quarantine regulation. The formation of bacterial biofilms, gums and tyloses occlude xylem vessel and then restrict xylem flow. The exhibited symptoms of PD in the grapevines include leaf marginal necrosis, chlorosis, and matchstick petiole. This insect-borne bacterial disease and its vectors have been investigated since 2002 in central Taiwan. Bothrogonia ferruginea (Fabricius, 1787) was considered as a candidate vector based on the positive detection for X. fastidiosa by PCR from field-collected insects. In this study, the basic ecological and biological information for B. ferruginea, including field surveys and life history parameters, and transmission efficiency of X. fastidiosa to grapevines were studied. The field survey data demonstrated that the B. ferruginea population peak occurred in April and May in Miaoli County and from July to August in Nantou County. The developmental time of B. ferruginea reared on pilose beggarticks (Bidens pilosa var. radiata) at 25oC from egg to fifth instar nymph, were 8.4, 8.2, 9.2, 15.4, 20.4, and 18.5 d, respectively. The adult longevity of female and male was 36.1 ± 9.6 and 32.3 ± 6.0 d, respectively. Forty two to seventy percentage of B. ferruginea acquired X. fastidiosa from field-collected infected grapevines within 24 h acquisition assess period in grouping vectors trial. Inoculation efficiency for grouped and individual vector trials was 18.2 and 6.7%, respectively. Insect-inoculated plants did not show typical symptoms of PD until 4 months post-inoculation and X. fastidiosa could be isolated from infected plants. Successful acquisition and transmission of X. fastidiosa to healthy grapevines by B. ferruginea suggesting this leafhopper was the insect vector for the transmission of the PD to grapevines. Although the population density and transmission rate of B. ferruginea suggested that it has the low possibility in triggering PD epidemic, the adult longevity and high consumption rate resulted in its high acquisition and retention ability. Additionally, in view of the body size as well as strong flight ability might imply that this vector plays an important role in reservoir and dissemination for X. fastidiosa. Therefore, a right-timing control of this vector should not be ignored. According to the data from field survey and life history of B. ferruginea, the control action against PD vector should be taken from March to August around epidemic area in Miaoli County and Taichung City, Taiwan. The management of this vector should pay attention to weeding around vineyard, especially pilose beggarticks, an appropriate host plant of B. ferruginea. In further study, we will aim at the microbial control with entomopathogenic fungi against this vector to suppress the occurrence of PD.