Ellis M L, Broders K D, Paul P A, Dorrance A E
Department of Plant Pathology, The Ohio State University, Wooster 44691.
Plant Dis. 2011 Apr;95(4):401-407. doi: 10.1094/PDIS-05-10-0317.
Fusarium graminearum causes seed decay and damping-off of soybean. This study evaluated the effect of inoculum density of F. graminearum, temperature, and fungicide seed treatments on disease development. To determine the optimum conditions for disease development, individual soybean seed was inoculated with 100 μl of a suspension of 2.5 × 10, 2.5 × 10, 2.5 × 10, or 2.5 × 10 macroconidia/ml in a rolled-towel assay at temperatures of 18, 22, and 25°C. Inoculum concentrations of 2.5 × 10 macroconidia/ml or higher were necessary for optimum disease development at all temperatures. The efficacy of captan, fludioxonil, mefenoxam + fludioxonil, azoxystrobin, trifloxystrobin, and pyraclostrobin as seed treatments was then evaluated with the same assay at 2.5 × 10 and 2.5 × 10 macroconidia/ml. Seed treated with captan at 61.9 g a.i. or fludioxonil at 2.5 or 5.0 g a.i. per 100 kg developed smaller lesions than other seed treatments and the nontreated control. Based on these results, there are limited choices in fungicide seed treatments for managing this seedling disease, and it is possible that shifts in seed treatment products may have played a role in the recent emergence of this soybean pathogen.
禾谷镰刀菌会导致大豆种子腐烂和猝倒病。本研究评估了禾谷镰刀菌接种密度、温度以及杀菌剂种子处理对病害发展的影响。为确定病害发展的最佳条件,在卷纸试验中,将单个大豆种子接种100 μl浓度为2.5×10、2.5×10、2.5×10或2.5×10个大分生孢子/ml的悬浮液,温度分别为18、22和25°C。在所有温度下,接种浓度为2.5×10个大分生孢子/ml或更高时病害发展最佳。然后在接种浓度为2.5×10和2.5×10个大分生孢子/ml时,用相同试验评估了克菌丹、咯菌腈、甲霜灵+咯菌腈、嘧菌酯、肟菌酯和吡唑醚菌酯作为种子处理剂的效果。用61.9 g有效成分/100 kg的克菌丹或2.5或5.0 g有效成分/100 kg的咯菌腈处理的种子,其病斑比其他种子处理和未处理对照更小。基于这些结果,在用于防治这种幼苗病害的杀菌剂种子处理方面选择有限,种子处理产品的变化可能在这种大豆病原菌近期的出现中起到了作用。