柑桔黄龙病的病原在木虱体内循回期的研究

STUDY ON LATENT PERIOD OF PATHOGEN OF CITRUS HUANGLUNGBIN IN CITRUS PSYLLA,DIAPHORINA CITRI KUW.

本研究应用生物测定和电镜检验的方法,探讨黄龙病病原在其介体昆虫(柑桔木虱)体内的循回期。前者的结果表明,其循回期长短不一,短的为3天或少于3天,长的达26—27天。木虱成虫能终身携带病原。获“毒”饲育若虫新羽化的成虫也能传病。其中,羽化后1天和2—5天便能传病的单虫分别占供试虫(组)数的3%和5%。电镜检验结果,在获“毒”饲育后3天的成虫唾液腺细胞内能观察到病原体,有力支持了采用生物测定循回期的可靠性。根据由获“毒”饲育若虫新羽化的成虫就能传病的新认识,建议治虫防病的重点应放在治卵和若虫上。

The latent period of the pathogen of Citrus Huanglungliu in Diaphorina citri was studied by means of its biology and the exan ination under electron microscope. The result of the former study showed that its latent period varied greatly in length. The minimum latent period was 3 or shorter than 3 days and the maximum was. 26-27 days. In a series of. the transmission tests, a single adult or a group of adult could transmit Huanglungbin to several ponkan seedlings and some adults could retain their infectivity through the whole stage. The adults emerging from infected nymphs could also transmit the disease to the seedlings. Moreover, the single adults transmitted the disease on the day of emerging and the others transmitted on 2-5 days after emerging give 30% and 50% of the total adults tested respectively. The results of examination under an electron microscope indicated that the pathogen of Citrus Huanglungbin could be found in the cells of salivary gland one cay after acquisition feeding. It confirmed the res(?)lt of biological tests that the minimum latent period was 3 or shorter than 3 days. According to the fact that the adults emerging from infected nymphs could transmit the disease to healthy trees, we suggested that the key to the control of Huanglungbin should lie in controlling D, citri at its egg and nymph stages.