Summary Various methods were tested to control the annual grass Rottboellia exaltata L.f. in maize (Zea mays L.) under small‐farm conditions in Bukidnon Province, Mindanao, Philippines during 1977 and 1978. No single method was satisfactory. Despite adequate early season control, late‐germinating Rottboellia tillered profusely. By harvest, plots had heavy infestations and were carpeted with seed. At harvest, untreated controls averaged 8·6 t Rottboellia dry matter ha−1 and only half the maize yield of handweeded plots. The ‘karase’ spike‐tooth harrow, or 0·2 kg paraquat ha−1, effectively removed Rottboellia flushes before maize emergence, but these techniques delayed planting, which can intensify downy mildew disease (Sclerospora sp.). Even though handweeding increased maize yields and decreased Rottboellia dry weights, it is impractical on typical 3‐ to 5‐ha maize farms. Mungbean (Vigna radiata (L.) Wilczek var. aureus), intercropped with maize, suppressed Rottboellia initially. Openings caused by mungbean harvest, however, allowed explosive late‐season weed growth in maize. Three herbicide treatments were as effective as handweeding: pendimethalin plus atrazine, either banded over the maize row (followed by cultivation), or broadcast; and pendimethalin followed by 2, 4‐D, both broadcast. In one experiment, low‐cost practices, including weed flush removal, cultivation, or handweeding, provided high net returns, whereas expensive herbicide treatments produced low net returns. Fertilizer, applied without weed control, increased maize yield 62%. Without fertilizer, weed control increased yield 107%. Combining the two raised yield 167%.