Anderson T R, Tenuta A U
Greenhouse and Processing Crops Research Centre, Agriculture and Agri-food Canada, Harrow, ON N0R 1G0.
Field Crops, Pest Management Specialist, Ontario Ministry of Agriculture, Food and Rural Affairs, Ridgetown College of Agricultural Technology, Ridgetown, ON N0P 2C0.
Plant Dis. 1998 Apr;82(4):448. doi: 10.1094/PDIS.1998.82.4.448D.
Sudden death syndrome (SDS), caused by Fusarium solani (Mart.) Sacc. f. sp. glycines, is a disease of soybean (Glycine max (L.) Merr.) in several central and southern states of the United States. In Ontario, Canada, individual soybean plants with typical foliar symptoms of SDS (1) have been observed annually in Kent County since 1993 but the causal organism was not isolated or identified. In 1996, plants with symptoms of SDS were observed in six fields located in Essex, Kent, and Lambton counties. Interveinal chlorosis and necrosis occurred on top leaves of affected plants and a pale brown discoloration occurred in the vascular system in lower stems and upper tap roots. Slow-growing isolates of F. solani f. sp. glycines with typical blue sporodochia were isolated from symptomatic plants on acidified potato dextrose agar (1). Root inoculation of 15 2-week-old seedlings with colonized oat kernals with each of five single-spore isolates caused typical SDS symptoms on 5-week-old soybean plants of cvs. Conrad, A2540, S19-90, and Ripley in the greenhouse. The severity and incidence of symptoms varied with cultivar and isolate. Of 125 plants inoculated, 6% of Conrad, 10% of A2540, 14% of S19-90, and 17% of Ripley plants developed foliar symptoms. Symptoms did not develop on noninoculated controls. F. solani f. sp. glycines was reisolated from roots of symptomatic plants. Although Ripley is known to have resistance to SDS (2), foliar and root symptoms developed following inoculation with each Ontario isolate of F. solani f. sp. glycines. Yield losses in 1996 were difficult to assess because of the scattered distribution of diseased plants in most fields. Diseased plants had few and poorly filled pods. In two fields, soybean growth was severely restricted in large areas covering 2 ha each; however, soybean cyst nematode (SCN) was present in both fields. SCN was present at all locations. Although total yield losses are currently low, it is evident that F. solani f. sp. glycines causing SDS has become widely distributed in southwest Ontario and disease severity is increasing. References: (1) K. W. Roy et al. Phytopathology 79:191, 1989. (2) P. A. Stevens et al. Crop Sci. 33:929, 1993.
猝死综合征（SDS）由大豆尖镰孢（Fusarium solani (Mart.) Sacc. f. sp. glycines）引起，是美国中部和南部几个州大豆（Glycine max (L.) Merr.）的一种病害。在加拿大安大略省，自1993年以来，肯特县每年都能观察到具有猝死综合征典型叶部症状的单株大豆植株（1），但致病生物未被分离或鉴定。1996年，在埃塞克斯、肯特和兰伯顿县的6块田地中观察到有猝死综合征症状的植株。受影响植株顶部叶片出现脉间黄化和坏死，下部茎和上部主根的维管束系统出现浅褐色变色。在酸化马铃薯葡萄糖琼脂上从有症状的植株中分离出了具有典型蓝色分生孢子座的生长缓慢的大豆尖镰孢菌株（1）。用5个单孢分离株中的每一个对15株2周龄幼苗进行根部接种，接种定殖燕麦粒后，在温室中5周龄的Conrad、A2540、S19 - 90和Ripley品种大豆植株上引发了典型的猝死综合征症状。症状的严重程度和发病率因品种和分离株而异。在接种的125株植株中，Conrad品种有6%、A2540品种有10%、S19 - 90品种有14%、Ripley品种有17%出现叶部症状。未接种的对照植株未出现症状。从有症状植株的根部重新分离出了大豆尖镰孢菌株。尽管已知Ripley品种对猝死综合征有抗性（2），但接种安大略省每个大豆尖镰孢分离株后，叶部和根部都出现了症状。由于1996年大多数田地中病株分布分散，产量损失难以评估。病株结荚少且籽粒饱满度差。在两块田地中，大面积（每块2公顷）的大豆生长受到严重限制；然而，这两块田地中都存在大豆胞囊线虫（SCN）。所有地点都存在大豆胞囊线虫。尽管目前总产量损失较低，但很明显，引起猝死综合征的大豆尖镰孢已在安大略省西南部广泛分布，病害严重程度正在增加。参考文献：（1）K. W. Roy等人，《植物病理学》79:191，1989年。（2）P. A. Stevens等人，《作物科学》33:929，1993年。
