Two major weeds in rice in the Philippines, Sphenochlea zeylanica Gaertn. and Echinochloa crus-galli (L.) Beauv., are controlled with chemical and cultural methods. In the 1980s, after >10 years of continuous use of 2,4-D, S. zeylanica evolved resistance to the chemical in those rice fields that had been treated with 2,4-D once or twice every cropping season. In the 1990s, E. crus-galli evolved resistance to butachlor and propanil in rice monocrop areas where both herbicides were used continuously for 7–9 years. Rice farmers continue to use 2,4-D, butachlor and propanil extensively and are often unaware of herbicide resistance or the potential for cross-resistance, its causes or its implications. In order to control herbicide-resistant E. crus-galli, farmers are shifting to locally available herbicides with different modes of action, such as bispyribac, an acetolactate synthase inhibitor, and cyhalofop, an acetyl coenzyme A carboxylase inhibitor. Follow-up manual weeding or rotary weeding after herbicide spraying, a common farmers’ practice, removes the susceptible and resistant biotypes and could help to delay or prevent the evolution of resistance. Although the resistance mechanisms of both weeds are not determined yet, they could be related to enhanced degradation that is similar to the mechanisms that are shown by the resistant biotypes in other countries.

中文翻译：

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菲律宾的抗除草剂杂草：现状和抗性机制

菲律宾水稻中的两种主要杂草 Sphenochlea zeylanica Gaertn。和 Echinochloa crus-galli (L.) Beauv.，用化学和培养方法控制。在 1980 年代，在连续使用 2,4-D 超过 10 年之后，S. zeylanica 在每个种植季节用 2,4-D 处理过一次或两次的稻田中进化出对该化学品的抗性。在 1990 年代，E. crus-galli 在连续使用这两种除草剂 7-9 年的水稻单作区进化出对丁草胺和丙苯胺的抗性。稻农继续广泛使用 2,4-滴、丁草胺和敌草胺，并且往往不知道除草剂抗性或交叉抗性的可能性、其原因或影响。为了控制耐除草剂的 E. crus-galli，农民正在转向当地可用的具有不同作用模式的除草剂，如双嘧菌酯，一种乙酰乳酸合酶抑制剂，和cyhalofop，一种乙酰辅酶A羧化酶抑制剂。喷洒除草剂后进行后续人工除草或旋耕，这是农民的一种常见做法，可去除易感和抗药性生物型，有助于延缓或防止抗药性的演变。虽然两种杂草的抗性机制尚未确定，但它们可能与增强降解有关，这与其他国家抗性生物型所显示的机制相似。