Timila R D, Correll J C, Duwadi V R
Plant Pathology Division, Nepal Agricultural Research Council, Kathmandu, Nepal.
Department of Plant Pathology, University of Arkansas, Fayetteville.
Plant Dis. 2008 Feb;92(2):317. doi: 10.1094/PDIS-92-2-0317B.
Cultivation of brassica vegetables has the highest potential for generating income among more traditional rice and maize farmers in Nepal. Among brassica vegetables, the most important are cauliflower (Brassica oleracea var. botrytis L.) and cabbage (B. oleracea var. capitata L.). Although clubroot disease, caused by Plasmodiophora brassicae Woronin, has been observed in Nepal since 1993, severe and widespread epidemics have been observed since 2004 in the Bhaktapur, Kathmandu, Lalitpur, and Palung Valley production areas. Typical disease symptoms (1) are widespread, and disease severity has been particularly severe in the Kathmandu Valley and Palung/Daman area of the Makwanpur District. Many cauliflower fields in these areas have had as much as 100% yield loss between 2004 and 2006 with an estimated 40% overall loss from clubroot. Estimates from interviews with growers in the Palung production area during an intensive farmers' interaction program indicated that cauliflower production was reduced from 5 to 6 metric tons per household (1,500 m) prior to 2004 to <300 kg per household in 2004 and beyond. The economic loss in this area alone was estimated at $1.4 million in 2004 and 2005. Examination of transplant nurseries indicated that frequently >80% of the seedlings have symptoms of clubroot at the time of transplanting. Soil samples from throughout the production areas indicated that the sandy loam soils were predominately acidic (pH range of 4.2 to 7.2 with >90% below 6.0). Several management practices are being employed to reduce disease severity, including the use of clubroot resistant cultivars, raising the soil pH to >7.0 by using dolomitic lime, testing of the fungicide flusulfamide (Nebijin) and biopesticide Sanjeevani (Trichoderma viride), and biofumigation and solarization of the nursery beds in an effort to reduce disease pressure on transplant material. References: (1) G. R. Dixon. Compendium of Brassica Diseases. S. R. Rimmer et al., eds. American Phytopathological Society, St. Paul, 2007.
在尼泊尔，对于较为传统的水稻和玉米种植户而言，种植芸苔属蔬菜创收潜力最大。在芸苔属蔬菜中，最重要的是花椰菜（Brassica oleracea var. botrytis L.）和卷心菜（B. oleracea var. capitata L.）。虽然自1993年以来在尼泊尔就已发现由芸苔根肿菌（Plasmodiophora brassicae Woronin）引起的根肿病，但自2004年以来，在巴克塔普尔、加德满都、莱利普尔和帕隆山谷产区出现了严重且广泛的疫情。典型的病害症状（1）普遍存在，加德满都谷地以及马克万布尔区的帕隆/达曼地区病害尤为严重。在2004年至2006年间，这些地区的许多花椰菜田产量损失高达100%，据估计根肿病造成的总体损失为40%。在一次密集的农户交流项目中，对帕隆产区种植户的访谈估计表明，2004年之前每户（1500平方米）花椰菜产量为5至6公吨，而在2004年及之后降至每户不足300千克。仅该地区在2004年和2005年的经济损失估计就达140万美元。对移栽苗圃的检查表明，移栽时通常超过80%的幼苗有根肿病症状。来自整个产区的土壤样本表明，砂壤土大多呈酸性（pH值范围为4.2至7.2，超过90%低于6.0）。目前正在采用多种管理措施来降低病害严重程度，包括使用抗根肿病品种、使用白云石粉将土壤pH值提高到7.0以上、测试杀菌剂氟磺酰胺（Nebijin）和生物农药圣吉瓦尼（Trichoderma viride），以及对苗圃床进行生物熏蒸和日光消毒，以减轻移栽材料上的病害压力。参考文献：（1）G. R. Dixon。《芸苔属病害简编》。S. R. Rimmer等人编著。美国植物病理学会，圣保罗，2007年。
