Department of Entomology and Plant Pathology and NC Plant Sciences Initiative, North Carolina State University, Raleigh, NC 27606-7825.
Nematode Assay Section, Agronomic Division, North Carolina Department of Agriculture and Consumer Services, Raleigh, NC 27607.
Plant Dis. 2024 Sep;108(9):2855-2864. doi: 10.1094/PDIS-08-22-1877-RE. Epub 2024 Sep 4.
Root-knot nematodes (RKNs, spp.) are some of the most economically important and common plant parasitic nematodes in North Carolina (NC) cropping systems. Soil samples collected from fields planted with crops rotated with sweetpotato ( [L.] Lam.) in 39 NC counties in 2015 to 2018 were processed at the NC Nematode Assay Laboratory. The occurrence of second-stage juvenile (J2) RKN populations was examined based on collection year, month, county, and previous planted crop. The highest number of RKN-positive samples originated from Cumberland (53%), Sampson (48%), and Johnston (48%) counties. The highest average RKN population density was detected in Sampson (147 J2/500 cm of soil) and Nash (135 J2/500 cm of soil) counties, while Wayne (7 J2/500 cm of soil) and Greene (11 J2/500 cm of soil) counties had the lowest average RKN population density. is a new invasive species that is impacting sweetpotato growers of NC. The host status of an NC population of , the guava RKN, was determined by examining eggs per gram of fresh root (ER) and the final nematode egg population divided by the initial population egg count (reproductive factor, RF) in greenhouse experiments. This included 18 vegetable, field, and cover crops and weed species. The tomato 'Rutgers' was used as a susceptible control. Cabbage 'Stonehead', pepper 'Red Bull', and watermelon 'Charleston Gray' and 'Fascination' were hosts and had similar mean ER values to the positive control, ranging from 64 to 18,717. Among field crops, cotton, soybean 'P5018RX', and tobacco were hosts with ER values that ranged from 185 to 706. Members of the Poaceae family such as sweet corn () and sudangrass ( × ) were nonhosts to , and the mean ER values ranged from 1.85 to 7. The peanut 'Tifguard' and winter wheat () also had lower ER values than the vegetable hosts. Growers should consider planting less susceptible hosts or nonhosts such as peanut, sudangrass, sweet corn, and winter wheat in 2- to 3-year crop rotations to lower populations of this invasive nematode.
根结线虫（RKNs， spp.）是北卡罗来纳州（NC）作物系统中一些最重要和最常见的植物寄生线虫。2015 年至 2018 年，从种植甘薯（[L.] Lam.）轮作作物的 39 个 NC 县采集的土壤样本在 NC 线虫分析实验室进行处理。根据采集年份、月份、县和之前种植的作物，检查了第二代幼虫（J2）RKN 种群的发生情况。RKN 阳性样本数量最多的来自坎伯兰（53%）、桑普森（48%）和约翰斯顿（48%）县。桑普森（147 J2/500 cm 土壤）和纳什（135 J2/500 cm 土壤）县的平均 RKN 种群密度最高，而韦恩（7 J2/500 cm 土壤）和格林（11 J2/500 cm 土壤）县的平均 RKN 种群密度最低。是一种新的入侵物种，正在影响北卡罗来纳州的甘薯种植者。通过在温室实验中检查每克新鲜根中的卵数（ER）和最终线虫卵种群除以初始种群卵计数（繁殖因子，RF），确定了 NC 种群的宿主地位，该种群为番石榴根结线虫。这包括 18 种蔬菜、大田和覆盖作物和杂草种类。番茄'Rutgers'被用作敏感对照。白菜'Stonehead'、辣椒'Red Bull'和西瓜'Charleston Gray'和'Fascination'是宿主，与阳性对照的平均 ER 值相似，范围从 64 到 18717。在大田作物中，棉花、大豆'P5018RX'和烟草是宿主，ER 值范围从 185 到 706。甜玉米（）和苏丹草（ × ）等禾本科植物是非宿主，平均 ER 值范围从 1.85 到 7。花生' Tifguard'和冬小麦（）的 ER 值也低于蔬菜宿主。种植者应考虑在 2 至 3 年的轮作中种植低敏感宿主或非宿主，如花生、苏丹草、甜玉米和冬小麦，以降低这种入侵线虫的种群数量。
