University of Arkansas System, Division of Agriculture, Department of Entomology and Plant Pathology, Lonoke Extension Center, Lonoke, AR 72086.
Plant Dis. 2024 Nov;108(11):3400-3405. doi: 10.1094/PDIS-04-24-0936-RE. Epub 2024 Nov 5.
Cyclobutrifluram, a succinate dehydrogenase inhibitor fungicide, is being evaluated as a seed-applied nematicide in cotton and soybean to manage plant-parasitic nematodes. Currently, there is no information on the toxicity, ovicidal activity, nematode recovery, or effects on nematode infection for or after exposure to low concentrations of cyclobutrifluram. Nematode toxicity assays were performed in aqueous solutions of cyclobutrifluram, and root infection assays were conducted on tomato. Nematode paralysis was observed after 2 h of exposure to 0.5 μg/ml cyclobutrifluram for both nematode species. Based on an assay of nematode motility, the 2-h effective concentration of fungicide required for 50% growth inhibition (EC) value for and was 0.48 and 1.07 μg/ml, respectively. In a comparable assay with a similar nematicide, continuous exposure to 0.5 μg/ml cyclobutrifluram for 24 h resulted in at least 45% more immotile nematodes for both species compared with those treated with 0.5 μg/ml fluopyram. Continuous exposure to concentrations greater than 1.0 μg/ml suppressed hatching for both species compared with the water control. Nematode recovery from paralysis was greater than 80% for and 24 h after nematodes were rinsed and removed from a 1-h treatment to their respective 2-h EC concentrations. Nematode infection of tomato roots was reduced following a 1-h treatment with aqueous solutions of cyclobutrifluram, ranging from 0.12 to 0.48 μg/ml for and 0.27 to 1.07 μg/ml for . Overall, the toxicity of cyclobutrifluram to these nematode species was greater than that of fluopyram, and although the effects of cyclobutrifluram were reversible, low concentrations were effective at reducing the ability of both nematodes to infect tomato roots.
环丙氟虫胺是一种琥珀酸脱氢酶抑制剂类杀菌剂，正作为一种杀线虫剂用于棉花和大豆种子处理，以防治植物寄生线虫。目前，尚无关于在低浓度环丙氟虫胺暴露后对线虫的毒性、杀卵活性、线虫回收或对线虫感染影响的信息。在环丙氟虫胺的水溶液中进行了线虫毒性测定，在番茄上进行了根感染测定。两种线虫在暴露于 0.5μg/ml 环丙氟虫胺 2 小时后均出现麻痹。根据线虫运动性测定， 和 的 2 小时有效浓度（EC）值分别为 0.48 和 1.07μg/ml，用于 50%生长抑制。在具有类似杀线虫剂的类似测定中，与用 0.5μg/ml 氟吡菌胺处理的线虫相比，连续暴露于 0.5μg/ml 环丙氟虫胺 24 小时会导致两种线虫的无活力线虫增加至少 45%。与水对照相比，连续暴露于浓度大于 1.0μg/ml 的环丙氟虫胺会抑制两种线虫的孵化。从麻痹中恢复的线虫数量大于 80%， 和 在将线虫从 1 小时处理中冲洗并去除至各自的 2 小时 EC 浓度后 24 小时。用环丙氟虫胺水溶液处理 1 小时后，番茄根线虫感染减少， 和 的浓度范围分别为 0.12 至 0.48μg/ml 和 0.27 至 1.07μg/ml。总体而言，环丙氟虫胺对这些线虫的毒性大于氟吡菌胺，尽管环丙氟虫胺的作用是可逆的，但低浓度就能有效降低两种线虫感染番茄根的能力。
