How to manage weedy rice
Weedy rice is closely related to cultivated rice and is a serious threat in direct-seeded rice. Once fields are infested, the costs of control can be very high. At present, no single management technique can effectively control weedy rice. Weedy rice is found in many rice areas in different regions of the Philippines.
What does weedy rice look like?
- Weedy rice can be taller or shorter than or as tall as cultivated rice
- Weedy rice can have closed or open panicles
- Flag leaves can be erect or droopy
- Awns can be absent, short or long
Weedy rice shatters easily
Gripping a nearly ripe panicle of weedy rice will cause many of the grains to fall (shatter). At harvest, many weedy rice seeds are left on the soil surface and these germinate when conditions are favorable.
Control/Management
- Manual weeding/Roguing remove weedy rice panicles by hand. At the heading/flowering stages, cut them and leave them in the field. Weedy rice should be removed to prevent future infestations.
- During land preparation, uniformly distribute rice straw and burn straw to destroy weedy rice seeds on the soil surface.
- Use preplant herbicide or tillage to destroy weedy rice seedlings. Wet tillage destroys weedy rice seedlings and promotes new emergence. Final tillage and land leveling result in more even water depth with flooding and help limit germination and emergence of weedy rice seedlings.
