Department of Plant Pathology, University of Georgia, Tifton, GA 31793.
Crop Protection and Management Research Unit, USDA ARS, Tifton, GA 31793.
Plant Dis. 2019 Dec;103(12):3161-3165. doi: 10.1094/PDIS-04-19-0836-RE. Epub 2019 Sep 23.
The southern root-knot nematode (RKN), , is particularly difficult to manage because of high susceptibility of all commercial cucumber () cultivars to this nematode. Growers have conventionally relied on nematicide applications to control RKN. Two microplot experiments were conducted in which four nonfumigant nematicides, oxamyl, fluopyram, fluensulfone, and fluazaindolizine, were examined for their efficacy in reducing gall severity and postharvest soil nematode numbers in microplots inoculated with increasing inoculation densities (1,000, 5,000, 10,000, and 20,000 nematodes/microplot), and improving growth and yield of cucumber. Nematicides were applied 1 day prior to transplanting cucumber seedlings, except fluensulfone, which was applied 7 days before transplanting. At harvest, root gall indices differed significantly ( < 0.0001) among nematode inoculation densities and nematicides. All four nematicides were effective in reducing the root gall index when compared with the untreated control on a consistent basis at all inoculation densities. At the lowest inoculation density, no significant difference in gall index or final population density was observed among nematicides; however, gall index increased with increasing nematode inoculation densities in nematicide-treated microplots. Correlations between gall index and inoculation density clearly showed that soil treatment with fluensulfone, fluazaindolizine, or fluopyram was more effective in reducing gall severity than treatment with oxamyl. Regression analysis also indicated no significant effect of nematode inoculation densities on yield of cucumber treated with these nematicides. Results of this study will provide guidance for improving nematicide efficiencies in soil with varying inoculation densities of RKN.
南方根结线虫（RKN）特别难以防治，因为所有商业黄瓜品种对这种线虫都非常敏感。种植者通常依赖杀线虫剂来控制 RKN。进行了两项微区试验，检验了四种非熏蒸杀线虫剂（氧氨酯、氟吡菌酰胺、 fluensulfone 和 fluazaindolizine）在降低接种密度（1000、5000、10000 和 20000 条线虫/微区）增加时微区中瓜的严重度和收获后土壤线虫数量的功效，以及提高黄瓜的生长和产量。杀线虫剂在移栽黄瓜幼苗前 1 天施用，除 fluensulfone 外，它在移栽前 7 天施用。收获时，根瘤指数因线虫接种密度和杀线虫剂而异（<0.0001）。与未处理的对照相比，所有四种杀线虫剂在所有接种密度下均能有效降低根瘤指数。在最低接种密度下，杀线虫剂处理的微区中，瘤指数或最终种群密度之间没有显著差异；然而，随着线虫接种密度的增加，瘤指数在杀线虫剂处理的微区中增加。瘤指数与接种密度之间的相关性清楚地表明，与 oxamyl 相比，fluensulfone、fluazaindolizine 或 fluopyram 处理土壤在降低瘤严重程度方面更为有效。回归分析还表明，这些杀线虫剂处理对黄瓜产量没有显著影响，与线虫接种密度无关。本研究的结果将为提高具有不同 RKN 接种密度土壤中杀线虫剂效率提供指导。
