Osei Kingsley, Gowen Simon R, Pembroke Barbara, Brandenburg Rick L, Jordan David L
Former graduate student, Professor, and Professor, Department of Agriculture, University of Reading, School of Agriculture, Policy, and Development, Box 237, Earley Gate, RG6 6AR, Reading, UK.
J Nematol. 2010 Sep;42(3):173-8.
Root-knot nematode is an important pest in agricultural production worldwide. Crop rotation is the only management strategy in some production systems, especially for resource poor farmers in developing countries. A series of experiments was conducted in the laboratory with several leguminous cover crops to investigate their potential for managing a mixture of root-knot nematodes (Meloidogyne arenaria, M. incognita, M. javanica). The root-knot nematode mixture failed to multiply on Mucuna pruriens and Crotalaria spectabilis but on Dolichos lablab the population increased more than 2- fold when inoculated with 500 and 1,000 nematodes per plant. There was no root-galling on M. pruriens and C. spectabilis but the gall rating was noted on D. lablab. Greater mortality of juvenile root-knot nematodes occurred when exposed to eluants of roots and leaves of leguminous crops than those of tomato; 48.7% of juveniles died after 72 h exposure to root eluant of C. spectabilis. The leaf eluant of D. lablab was toxic to nematodes but the root eluant was not. Thus, different parts of a botanical contain different active ingredients or different concentrations of the same active ingredient. The numbers of root-knot nematode eggs that hatched in root exudates of M. pruriens and C. spectabilis were significantly lower (20% and 26%) than in distilled water, tomato and P. vulgaris root exudates (83%, 72% and 89%) respectively. Tomato lacks nematotoxic compounds found in M. pruriens and C. spectabilis. Three months after inoculating plants with 1,000 root-knot nematode juveniles the populations in pots with M. pruriens, C. spectabilis and C. retusa had been reduced by approximately 79%, 85% and 86% respectively; compared with an increase of 262% nematodes in pots with Phaseolus vulgaris. There was significant reduction of 90% nematodes in fallow pots with no growing plant. The results from this study demonstrate that some leguminous species contain compounds that either kill root-knot nematodes or interfere with hatching and affect their capacity to invade and develop within their roots. M. pruriens, C. spectabilis and C. retusa could be used with effect to decrease a mixed field populations of root-knot nematodes.
根结线虫是全球农业生产中的一种重要害虫。在一些生产系统中，尤其是发展中国家资源匮乏的农民，轮作是唯一的管理策略。在实验室中对几种豆科覆盖作物进行了一系列实验，以研究它们管理根结线虫混合物（南方根结线虫、爪哇根结线虫、花生根结线虫）的潜力。根结线虫混合物在多毛黧豆和美丽猪屎豆上无法繁殖，但在扁豆上，每株接种500和1000条线虫时，线虫数量增加了两倍多。多毛黧豆和美丽猪屎豆上没有根瘤，但在扁豆上观察到了根瘤评级。与番茄相比，当暴露于豆科作物的根和叶的洗脱液时，根结线虫幼虫的死亡率更高；暴露于美丽猪屎豆根洗脱液72小时后，48.7%的幼虫死亡。扁豆的叶洗脱液对线虫有毒，但根洗脱液无毒。因此，一种植物的不同部位含有不同的活性成分或相同活性成分的不同浓度。在多毛黧豆和美丽猪屎豆的根分泌物中孵化的根结线虫卵的数量分别显著低于蒸馏水、番茄和菜豆根分泌物中的数量（20%和26%分别低于83%、72%和89%）。番茄缺乏在多毛黧豆和美丽猪屎豆中发现的对线虫有毒的化合物。用1000条根结线虫幼虫接种植物三个月后，种植多毛黧豆、美丽猪屎豆和圆叶猪屎豆的花盆中线虫数量分别减少了约79%、85%和86%；相比之下，种植菜豆的花盆中线虫数量增加了262%。在没有种植植物的休耕花盆中线虫数量显著减少了90%。这项研究的结果表明，一些豆科物种含有能够杀死根结线虫或干扰孵化并影响其在根内侵入和发育能力的化合物。多毛黧豆、美丽猪屎豆和圆叶猪屎豆可以有效地用于减少根结线虫的混合田间种群。
