Syngenta, Greensboro, NC 27409.
FMC Corp., Philadelphia, PA 19104.
Plant Dis. 2019 Oct;103(10):2498-2504. doi: 10.1094/PDIS-11-18-2045-RE. Epub 2019 Aug 27.
Downy mildew is a yield-limiting disease of sunflower, caused by the pathogen . Zoospore infection of root tissue shortly after planting results in systemic infection, causing postemergence damping off or severe stunting and head sterility. Although fungicide-applied seed treatments can be an effective management tool, the pathogen is resistant to phenylamide fungicides in many growing regions, and other available fungicides have limited efficacy. Oxathiapiprolin, the first member of the piperidinyl thiazole isoxazoline fungicides, was evaluated for efficacy on downy mildew in field trials conducted from 2011 to 2015 in North Dakota. Throughout the course of the study, the rate range was narrowed from active ingredient (a.i.) at 0.45 to 116.0 µg a.i. seed to an optimal effective rate of 9.37 to 18.75 µg a.i. seed. Within that optimal range, the downy mildew incidence of sunflower planted with oxathiapiprolin-treated seed was significantly lower than the incidence in the nontreated sunflower in all 11 trials with disease pressure. Additionally, downy mildew incidence of sunflower planted with oxathiapiprolin-treated seed was significantly lower than sunflower planted with competitive commercially available fungicide-treated seed in 10 of those 11 trials. The use of oxathiapiprolin by sunflower growers is likely to reduce disease incidence and subsequent yield loss to downy mildew.
霜霉病是向日葵的一种限产疾病，由病原体引起。在种植后不久，游动孢子感染根组织会导致系统性感染，从而导致出苗后凋萎或严重矮化和头部不育。虽然杀菌剂拌种处理可以是一种有效的管理工具，但在许多生长地区，病原体对苯甲酰胺类杀菌剂具有抗性，并且其他可用的杀菌剂效果有限。噻唑并吡咯烷酮类的第一个成员恶唑噻二唑啉类杀菌剂，在北达科他州的田间试验中从 2011 年到 2015 年进行了防治霜霉病的功效评估。在研究过程中，有效成分（AI）从 0.45 至 116.0 µg AI/种子的范围缩小到 9.37 至 18.75 µg AI/种子的最佳有效剂量。在该最佳范围内，在有病害压力的 11 个试验中，用恶唑噻二唑啉处理的种子种植的向日葵的霜霉病发病率明显低于未处理的向日葵的发病率。此外，在这 11 个试验中的 10 个试验中，用恶唑噻二唑啉处理的种子种植的向日葵的霜霉病发病率明显低于用竞争的商业上可用的杀菌剂处理的种子种植的向日葵的发病率。向日葵种植者使用恶唑噻二唑啉可能会降低霜霉病的发病率和随后的产量损失。
