【摘要】 <正> 甜菜丛根病于1950年在意大利北部帕河流域原料甜菜上首先发现。1960年在意大利中部和南部甜菜集中种植区蔓延。1964年这种病害危及意大利17个省区,使一万多公顷甜菜失去利用价值,造成部分糖厂倒闭。1971年发生面积占意大利种植面积的66％。CANVA(1958)和BONGZOVANNZ(1960)第一次描述了这种新病害,并命名为疯根病(Rhizomania)。1965年在日本甜菜制糖公司所进行的部分连作试验区中,发现类似病害,当时被视为原因不明的连作所造成的病害。称为甜菜连作病害状异常症状或异常生育症状(增田,1967)。1969年以后,成为日本北海道甜菜原料区的重要病害之一。更多还原

【Abstract】 It was found that a abnormal phenomena in the growing of some beet plants in Nei Mongol in 1978. Three symptomic typies mainly showed inleafage: withered, cholorosis and necrotic yellow vein. Quitely identical i symptom of roots. Lateral roots became brown, thin, necrosis and lose. And broken a large number of secondary lateral roots in where roots have necrotic lose appearing as whiskers. Infected plants would occur a series of physiological pathologic changes, cell have deformed, content of chlorophyll dropped, recoverable sugar and significant changes have taken place in content of amino acid, comparing with healthy plants, infected root yield decreased 30-80% and sugar content reduced 4-9.6% , but noxious nitrogen raised 22%. The virus particles isolated from infected roots were straightrods, helical consture. And 16-25 mμ wide, three typies of length. 360-420mμ. the long particles, 215-320 m() intermediate, 60-167 mμ short. The virus has a narrow host range. Hosts identified were. Tetragonia expansa, chenopodium quinoa, ch. amaranticolor and sugarbeet. The ring precipitation reaction taken place in virus purified solution of infected lateral roots, when it with BNYVV antiserum made by Tamada. The following results obtained in the research of 1979-82.1. Polymyxa, betae parasitized in all roots of infected plants.2. The amounts of resting spores and zoospores showed a positive correlation with ratio of infected plants.3.The resting spores drops inoculate to the beet roots of water culture, all showed that same sympton of Rizoma-nia of sugarbeet.4.The rough sap extracts of beet roots of water culture were inoculated to Tetragonia expansa showed symptom is same with purified virus solution of BNYVV. 5. The rough sap extracts of symptomatic roots after inoculation of friction were inoculated on Tetragonia expanse and sugarbeet without pathogenicity. Therefore, theabnormal growing beet plants was preliminary determined that spread by Polymyxa betae and caused by BNYVV. The main infection sources are infected soil , residues and manures bearing P. betae. The incidence is closely correlated to the amm amounts of fungus in the soil, temperature and moisture, fertility, soil texture, PH, crop for rotation and sowing time.更多还原