Weedy rice is morphologically similar to cultivated rice (Oryza sativa L.). It has biological characteristics that identify it as a weed. Its important weedy characteristics, that is, early and heavy seed shattering, makes it very difficult to control. Weedy rice has not been reported to be an important weed problem in transplanted, flooded rice. However, the shift to direct‐seeded rice (DSR) due to water issues and high costs of labor has increased reports of weedy rice becoming an expanding important problem in Vietnam, Malaysia, Thailand, and the Philippines. Experts believe that the growing adoption of DSR in Asian countries will result in the rise of weedy rice as one of the top troublesome weeds in rice production. Early and recent surveys in the Philippines have indicated the urgent need to increase awareness of weedy rice among farmers to allow the implementation of a number of effective location‐specific weed management strategies. These surveys and other studies conducted since weedy rice was first reported in 1991 confirmed that weedy rice and grass weed species caused major problems in DSR areas. About 35% of the 4.56 M ha harvested area in the country is planted with DSR. As cultivated and weedy rice are close relatives, it would be very difficult to implement management options very early in crop growth. However, a deeper understanding of the underlying traits of weedy rice can help develop a holistic approach toward effective and economic weed management.

中文翻译：

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杂草稻：菲律宾直接播种稻的一个日益严重的问题

杂草稻在形态上与栽培稻相似（水稻L.）。它具有将其识别为杂草的生物学特性。它具有重要的杂草特征，即种子早熟和重粒粉碎，因此很难控制。尚未报道杂草稻是移植的，淹水稻中的重要杂草问题。但是，由于水的问题和高昂的劳动力成本，人们转向直接播种水稻（DSR）的报道增加了关于杂草稻在越南，马来西亚，泰国和菲律宾日益严重的重要问题的报道。专家认为，亚洲国家对DSR的越来越多的采用将导致杂草稻成为水稻生产中最棘手的杂草之一。菲律宾的早期和近期调查表明，迫切需要提高农民对杂草稻的认识，以便实施一些针对特定地点的有效杂草管理策略。自从1991年首次报道杂草稻以来进行的这些调查和其他研究证实，杂草稻和草杂草物种是DSR地区的主要问题。该国456万公顷的收割面积中约有35％种植了DSR。由于栽培稻和杂草稻是近亲，因此很难在作物生长的早期就实施管理方案。但是，深入了解杂草稻的基本特性可以帮助开发一种全面的方法来进行有效和经济的杂草管理。自从1991年首次报道杂草稻以来进行的这些调查和其他研究证实，杂草稻和草杂草物种是DSR地区的主要问题。该国456万公顷的收割面积中约有35％种植了DSR。由于栽培稻和杂草稻是近亲，因此很难在作物生长的早期就实施管理方案。但是，深入了解杂草稻的基本特性可以帮助开发一种整体方法来进行有效和经济的杂草管理。自从1991年首次报道杂草稻以来进行的这些调查和其他研究证实，杂草稻和草杂草物种是DSR地区的主要问题。该国456万公顷的收割面积中约有35％种植了DSR。由于栽培稻和杂草稻是近亲，因此很难在作物生长的早期就实施管理方案。但是，深入了解杂草稻的基本特性可以帮助开发一种全面的方法来进行有效和经济的杂草管理。