Nault Brian A, Sandhi Ramandeep K, Harding Riley S, Grundberg Ethan A, Rusinek Teresa
Department of Entomology, Cornell University, Cornell AgriTech, 15 Castle Creek Drive, Geneva, NY 14456, USA.
Eastern New York Commercial Horticulture Program, Cornell Cooperative Extension, 18 Seward Avenue, Suite 300, Middletown, NY 10940, USA.
J Econ Entomol. 2022 Apr 13;115(2):618-623. doi: 10.1093/jee/toac016.
Allium leafminer, Phytomyza gymnostoma Loew (Diptera: Agromyzidae), is an invasive pest of allium crops in North America. Spinosyn insecticides, spinetoram and spinosad, have been effective choices for managing P. gymnostoma infestations in allium crops, but their use should be optimized for economical and resistance management purposes. In New York from 2018 through 2020, performance of each spinosyn insecticide was evaluated by making two applications spaced either 1 or 2 wk apart beginning at various intervals after P. gymnostoma was first detected in the field; a weekly spray program also was included. Results indicated that weekly applications of each spinosyn insecticide provided ≥98% reduction of P. gymnostoma densities in scallions and leeks relative to the untreated control. Spinetoram applied twice, regardless of initial timing and duration between sprays, provided an acceptable level of P. gynostoma control (71 to 98% reduction in densities relative to the untreated control). Spinosad also was effective when applied twice (85 to 95% reduction in densities relative to the untreated control), but not when sprays were made consecutively beginning when P. gymnostoma was first detected and not when the P. gymnostoma infestation was extremely high (i.e., 38 insects per plant in the untreated control). Management of P. gymnostoma with spinosyns can be successful with only two applications, but control tended to be best when first applied 2 to 3 wk after initial detection. Optimizing applications of spinetoram and spinosad will save growers time, reduce insecticide costs, and mitigate resistance development without significantly increasing the risk of yield reduction.
葱斑潜蝇（Phytomyza gymnostoma Loew，双翅目：潜蝇科）是北美洲葱属作物的一种入侵性害虫。多杀菌素类杀虫剂，如乙基多杀菌素和多杀菌素，是防治葱属作物中葱斑潜蝇侵害的有效选择，但为了经济和抗药性管理目的，应优化其使用。在纽约，2018年至2020年期间，通过在田间首次发现葱斑潜蝇后的不同间隔开始，进行两次间隔1周或2周的施药来评估每种多杀菌素类杀虫剂的性能；还包括每周喷雾方案。结果表明，相对于未处理对照，每周施用每种多杀菌素类杀虫剂可使葱和韭菜中的葱斑潜蝇密度降低≥98%。无论初始施药时间和喷雾间隔时长如何，施用两次乙基多杀菌素都能提供可接受的葱斑潜蝇防治水平（相对于未处理对照，密度降低71%至98%）。多杀菌素施用两次也有效（相对于未处理对照，密度降低85%至95%），但在首次发现葱斑潜蝇时开始连续喷雾时无效，且在葱斑潜蝇侵害极高时（即未处理对照中每株有38头昆虫）也无效。使用多杀菌素类杀虫剂防治葱斑潜蝇只需两次施药即可成功，但在首次发现后2至3周首次施药时防治效果往往最佳。优化乙基多杀菌素和多杀菌素的施药将节省种植者时间、降低杀虫剂成本并减轻抗药性发展，同时不会显著增加产量降低的风险。
