广东新发生流行的水稻橙叶病的鉴定

 1991~1992年广东茂名市的水稻约2万公顷发黄。用电光叶蝉Reclia dorsalis(Motsch)接种3叶龄稻苗,在平均气温28℃下,潜育期为8~36天;主要症状为病株矮,叶片竖直、橙黄至金黄色;部分病叶纵卷干枯;多数病苗早枯死。四环素液浸病稻根可明显延迟死亡。介体昆虫为电光叶蝉。而黑尾蝉Nephotettix cincticeps(Uhler)、二条(大斑)叶蝉N.apicalis(Motsch)和二点叶蝉N.virescence(Distant)以及虱Nilaparvata lugens(Stal)等均不传病。电光叶蝉最短获毒和最短传毒饲育期分别为<2min和<5min.期在室温25~30℃下,约为7~26天,保毒虫能终生传毒,但有间歇传病现象。在病叶脉韧皮筛管细胞毒叶蝉唾腺切片中均可见大量多形态的类菌原体,大小为75~639nm。据此认为本病与1980年云南十年代在东南亚报道的水稻橙叶病基本相同。

ON THE IDENTIFICATION OF RICE ORANGE LEAF OCCURRING IN GUANGDONG PROVINCE

About twenty-thousand hectares of rice became diseased in Moaming district, Guangdong province in 1991-1992. The main symptoms of the disease were dwarf ing, leaf became hard and extended straightly upward, orange yellow to golden yellow in color, some diseased leaves rolled longitudinally and dried quickly. Soaking the root system of the diseased plants with tetracycline solution could significantly delay their death-date. Zig-Zag rice leaf hopper (Recilia dorsalis (Motsch)) was found to be the only insect vector. Rice leaf hopper (Nephotettix cincticeps (Uhler)) while the leaf hopper (N. apicalis (Motsch), N. virescence (Distant) and the brown planthopper Nilaparvada lugens (Stal) could not transmit the disease. The shortest acquisition feeding period and the shortest transmission feeding period were respectively 2 minutes and 5 minutes. The circulation period in the insect vectors was 7-26 days under 25-30℃. The incubation period of the disease in rice seedlings was 8-36 days under average temperature of 28℃. A lot of polymorphic mycoplasma-like bodies were observed both in the ultra-thin section of phloem tissue of leaf veins and salivary gland of leaf hopper vector under electron microscopy, size varied from 75 to 639 nm. According to the above experimental results, it was considered that the disease was fundametally the same as the rice orange leaf disease reported from Yunnan province in 1980 and South-east Asia in 1970s.