The use of multiple insecticidal seed treatments in combination to control a greater spectrum of pests has been increasing in rice production in the U.S. Mid-South. The economic benefits of individual seed treatments in rice are well documented, but returns on investment (ROI) on combinations are unknown. Efficacy and economic returns of insecticidal seed treatments alone and in combination were evaluated through a series of five field trials conducted in Louisiana from 2018 to 2020. In all trials, treatments containing chlorantraniliprole or cyantraniliprole provided the best control of rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), and control was not significantly improved by the addition of a second insecticide. Insecticidal control of L. oryzophilus by all seed treatments was reduced in late-planted rice fields relative to rice planted within the recommended planting window. Control of the Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), did not improve rice yields. Fungicidal seed treatments generally protected rice yields over treatments without fungicides despite having no effect on early-season plant populations. All seed treatments provided returns on investment which ranged from $94.30 (fungicide only 2018) to $519.75/ha (chlorantraniliprole + thiamethoxam + fungicides in 2019–2020). Increased yields resulting from the use of multiple insecticides in combination appears to justify the added expense. Collectively, results demonstrate the immense value of insecticidal seed treatments to rice production in Louisiana and throughout the U.S. Mid-South. Future research efforts should aim to assess returns on seed treatments across a range of rice production conditions and to quantify the impacts of sporadic pests on rice yields.

在美国中南部的水稻生产中，结合使用多种杀虫剂种子处理来控制更广泛的害虫的做法正在增加。水稻单个种子处理的经济效益有据可查，但组合的投资回报 (ROI) 未知。通过 2018 年至 2020 年在路易斯安那州进行的一系列五项田间试验，评估了单独和联合杀虫种子处理的功效和经济效益。在所有试验中，含有氯虫苯甲酰胺或氰虫酰胺的处理对稻水象鼻虫Lissorhoptrus oryzophilus Kuschel（鞘翅目：Curculionidae），并且通过添加第二种杀虫剂没有显着改善控制。杀虫控制相对于在推荐种植窗口内种植的水稻，所有种子处理的L. oryzophilus在晚播稻田中均有所减少。控制墨西哥水稻螟，Eoreuma loftini (Dyar) (鳞翅目：蟹科)，并没有提高水稻产量。尽管对早季植物种群没有影响，但杀菌剂种子处理通常比不使用杀菌剂的处理保护水稻产量。所有种子处理都提供了投资回报，从 94.30 美元（仅 2018 年的杀菌剂）到 519.75 美元/公顷（氯虫苯甲酰胺 + 2019-2020 年噻虫嗪 + 杀菌剂）。组合使用多种杀虫剂导致的产量增加似乎证明了增加的费用是合理的。总的来说，结果表明杀虫剂种子处理对路易斯安那州和整个美国中南部水稻生产的巨大价值。未来的研究工作应旨在评估一系列水稻生产条件下种子处理的回报，并量化零星害虫对水稻产量的影响。