In 2002, a survey carried out in rice paddies in the Rio Grande do Sul (RS) state reported the occurrence of nine species of jointvetch (Aeschynomene). Due to their semi-aquatic habit, some species adapted to irrigated rice fields, which led to their being considered the worst broadleaf weed in RS. Although farmers have successfully implemented weed management practices, Aeschynomene plants have reportedly escaped chemical control. This study aims to identify the species of Aeschynomene that occur in rice fields in RS and to evaluate the reasons why escapes are occurring. A survey was carried out by collecting mature seeds from individual adult plants. A questionnaire on the management practices employed in each field was administered to 54 farmers and 18 extension agents, each of whom was responsible for one of the surveyed rice fields. This survey found four species of Aeschynomene are present in rice fields in RS: A. denticulata, A. indica, A. rudis, and A. sensitiva. The results suggest that the explanation for escapes may lie in the management practices adopted by farmers, which are focused on the control of weedy grasses. Escapes are also associated with problems such as the lack of irrigation uniformity and out-of-stage, late herbicide applications.

中文翻译：

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七香烯属。巴西南部稻田的鉴定和杂草处理

2002年，在南里奥格兰德州（Rio Grande do Sul）州的稻田中进行的一项调查报告，共有9种v虫（Aeschynomene）发生。由于其半水生习性，一些物种适应了灌溉稻田，这使其被认为是RS中最差的阔叶杂草。尽管农民已经成功实施了杂草管理实践，但据说Aeschynomene植物已经摆脱了化学控制。这项研究旨在确定七叶香烯的种类在RS的稻田中发生这种情况，并评估发生逃逸的原因。通过从单个成年植物中收集成熟种子来进行调查。向54个农民和18个推广人员发放了有关每个田间使用的管理实践的调查表，每个人负责一个被调查的稻田。这项调查发现RS中的稻田中存在四种Aeschynomene：A。denticulata，A。indica，A。rudis和A.敏感性。。结果表明，逃逸的原因可能在于农民采取的管理措施，这些管理措施侧重于控制杂草。逃逸还与诸如灌溉均匀性不足和后期除草剂使用落后等问题有关。