Key Laboratory of Pesticide Toxicology & Application Technique, College of Plant Protection, Shandong Agricultural University, Tai'an, Shandong 271018, China.
Tropical Research and Education Center, Department of Plant Pathology, University of Florida, IFAS, Homestead, FL 33031, U.S.A.
Plant Dis. 2023 Sep;107(9):2709-2715. doi: 10.1094/PDIS-12-22-2801-RE. Epub 2023 Sep 15.
Root-knot nematodes (RKNs) are harmful plant-parasitic nematodes of tomatoes which can cause significant yield losses. Therefore, there is increasing interest in exploring the application of bacterial nematicides. The bacterium TA-1 is a broad-spectrum biological control agent; however, its effect on RKNs control remains largely unclear. In this study, the toxicity of TA-1 against was investigated in vitro, and the potential of TA-1 to decrease infection of RKNs in tomato were evaluated in pot and field trials. Results showed that TA-1 exhibited high nematicidal activity against second-stage juveniles (J2s) and eggs of with 50% lethal concentration (LC) values of 5.80 and 7.00 × 10 colony forming units (CFU)/ml, respectively. In the pot experiments and field trials conducted in 2020 and 2021, tomato plants treated with TA-1 soil drench applied once at 3, 6, and 9 × 10 CFU/plant had significantly higher plant height and greater yield compared with the untreated control. Tomato yields of the treated plots with TA-1 in 2 consecutive years' field trials were between 53.4 to 66.1 and 52.8 to 61.5 t/ha, while they were 49.7 and 48.2 t/ha in the untreated control for each year, respectively. The lowest population densities of at 30 and 60 days after treatment were 119 and 135 J2s per 100 g soil in 2020 and 43 and 118 J2s in 2021 in TA-1-treated plots. The lowest gall index of 4.7 and 3.3 in 2020 and 2021, respectively, and the highest yield were all observed in the TA-1 at 9 × 10 CFU/plant treated plants, with no significant differences with the commercial control abamectin. These results provided a basis for further studies of TA-1 formulations, application doses, frequencies, and mechanisms of action, which are necessary before it could be used as a component of integrated management programs to manage RKNs in tomato production.
根结线虫（RKNs）是危害番茄的有害植物寄生线虫，可导致显著的产量损失。因此，人们越来越关注探索细菌杀线虫剂的应用。细菌 TA-1 是一种广谱生物防治剂；然而，其对 RKNs 控制的效果在很大程度上仍不清楚。在这项研究中，体外研究了 TA-1 对 的毒性，评估了 TA-1 在盆栽和田间试验中减少番茄 RKNs 感染的潜力。结果表明，TA-1 对第二代幼虫（J2）和 的卵表现出很高的杀线虫活性，其 50%致死浓度（LC）值分别为 5.80 和 7.00×10 个菌落形成单位（CFU）/ml。在 2020 年和 2021 年进行的盆栽试验和田间试验中，与未处理的对照相比，用 TA-1 土壤淋洗处理一次，每株施用 3、6 和 9×10 CFU/株的番茄植株具有更高的株高和更大的产量。在连续两年的田间试验中，用 TA-1 处理的地块的番茄产量在 53.4 到 66.1 和 52.8 到 61.5 吨/公顷之间，而未处理的对照分别为 49.7 和 48.2 吨/公顷。处理后 30 和 60 天的线虫种群密度最低，分别为每 100g 土壤 119 和 135 条 J2，2021 年 TA-1 处理的地块中，线虫种群密度最低，分别为每 100g 土壤 43 和 118 条 J2。2020 年和 2021 年，根结线虫的根结指数最低分别为 4.7 和 3.3，产量最高均出现在每株施用 9×10 CFU/株的 TA-1 处理植株中，与商业对照药剂阿维菌素无显著差异。这些结果为进一步研究 TA-1 制剂、施药剂量、频率和作用机制提供了依据，这是在将 TA-1 作为番茄生产中 RKN 综合管理计划的组成部分之前必须进行的研究。
