Research issues, challenges, and opportunities for weed management in Japan

Abstract This review states the outline of field crop production of Japan and weed problems to be solved. Field crop production of Japan is characterized by rice cultivation and small size farming. Most major field crops other than rice are imported, and various kinds and a very large amount of living weed seeds contaminate the imported grains. These alien weeds sometimes invade agricultural fields and cause serious losses of crop yields and reductions in the quality of agricultural products. Emergence of herbicide resistant biotypes of weeds, especially paddy weeds, is also issues to be solved. Weedy rice is recently emerging again due to the change of rice production system and the origin of recently emerging weedy rice is not clarified yet.