ABSTRACT This study evaluated the mycoherbicidal potential of Alternaria alternata (Fries.) Kiessler on cocklebur (Xanthium strumarium L.), a noxious weed in Algeria. Conidial suspension, a rapeseed-oil-based liquid formulation and a sodium-alginate-based solid formulation, all with 106 conidia/ml, as well as the herbicide (Mustang®) at a reduced dose (0.45 L/ha) were compared. Inoculum was applied on detached leaves of cocklebur under laboratory conditions and on 4–5 leaf stage cocklebur seedlings in pots in a greenhouse and in the field. Disease severity was highest following application of the liquid formulation in the detached leaf assay (95.5%) as well as in the pot (80%) and field (43%) experiments. Similarly, the oil-based liquid formulation reduced cocklebur height, root length and dry weight by up to 50%, 27% and 58%, respectively in pot trial and 40%, 51% and 45%, respectively in the field experiment. The conidial suspension ranked second in efficacy, followed by the solid formulation. Mustang® showed the highest herbicidal effect. None of the crops tested for host specificity including tomato, wheat, faba bean and zucchini was susceptible to the fungus. Our findings suggest that A. alternata has potential as biocontrol agent of cocklebur especially when applied in an oil-emulsion-based formulation.

中文翻译：

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Alternaria alternata (Fries.) Kiessler 及其制剂对寄主杂草 Xanthium strumarium L 的除草剂潜力。

摘要 本研究评估了 Alternaria alternata (Fries.) Kiessler 对苍耳 (Xanthium strumarium L.) 的杀菌潜力，苍耳草是阿尔及利亚的一种有害杂草。分生孢子悬浮液、基于菜籽油的液体制剂和基于海藻酸钠的固体制剂均具有 106 个分生孢子/ml，以及降低剂量 (0.45 L/ha) 的除草剂 (Mustang®)。在实验室条件下将接种物应用于苍耳的离体叶子上，并在温室和田间的盆中将接种物应用于 4-5 叶阶段的苍耳幼苗。在离体叶试验 (95.5%) 以及盆栽 (80%) 和田间 (43%) 试验中应用液体制剂后，病害严重程度最高。同样，油基液体配方将苍耳高度、根长和干重降低了 50%、27% 和 58%，在盆栽试验中分别为40%、51%和45%，在田间试验中分别为40%、51%和45%。分生孢子悬浮液在功效方面排名第二，其次是固体制剂。Mustang® 显示出最高的除草效果。包括番茄、小麦、蚕豆和西葫芦在内的所有经过宿主特异性测试的作物都对这种真菌敏感。我们的研究结果表明，A. alternata 具有作为苍耳生物防治剂的潜力，尤其是当应用于基于油乳液的制剂中时。