BACKGROUND The root-knot nematode Meloidogyne graminicola has become a serious threat to rice production as a result of the cultivation changes from transplanting to direct seeding. The nematicidal activity of Aspergillus welwitschiae have been investigated in vitro, and the disease control efficacy of the active compound has been evaluated under greenhouse and field conditions. RESULTS The active compound αβ-dehydrocurvularin (αβ-DC), isolated by nematicidal assay-directed fractionation, showed significant nematicidal activity against M. graminicola, with a median lethal concentration (LC50) value of 122.2 μg mL- 1. αβ-DC effectively decreased the attraction of rice roots to nematodes and the infection of nematodes and also suppressed the development of nematodes under greenhouse conditions. Moreover, αβ-DC efficiently reduced the root gall index under field conditions. CONCLUSIONS To our knowledge, this is the first report to describe the nematicidal activity of αβ-DC against M. graminicola. The results obtained under greenhouse and field conditions provide a basis for developing commercial formulations from αβ-DC to control M. graminicola in the future.

中文翻译：

---

从米曲霉中分离得到的αβ-去氢曲霉素可以有效抑制稻根中根结线虫Meloidogyne graminicola的行为和发育。

背景技术由于栽培技术从移植到直接播种的变化，根结线虫Meloidogyne graminicola已成为水稻生产的严重威胁。已在体外研究了魏氏曲霉的杀线虫活性，并已在温室和田间条件下评估了该活性化合物的防病功效。结果通过杀线虫剂测定直接分离分离出的活性化合物αβ-脱氢屈管素（αβ-DC）具有显着的杀线虫活性，对鼠疫分枝杆菌的致死浓度（LC50）值为122.2μgmL-1。αβ-DC有效减少了水稻根部对线虫的吸引和线虫的感染，并抑制了温室条件下线虫的生长。此外，在田间条件下，αβ-DC有效降低了根胆指数。结论据我们所知，这是第一个描述αβ-DC杀灭格氏疟原虫杀线虫活性的报告。在温室和田间条件下获得的结果为将来开发从αβ-DC到商业上控制灰纹分枝杆菌的商业配方提供了基础。