|
‘Red’
alert
Be on the lookout for red rice, |
|
|
By Vicky Boyd |
|
|
A weed considered by Southern growers to be a primary nemesis has been found in a California rice field, prompting state agricultural officials to take a multi-prong approach to eradicate it. “Red rice is a serious pest in the U.S. other than California, and its presence here—even on a limited scale—is cause for concern,” says Tim Johnson, executive director of the California Rice Commission in Sacramento. “We have to make sure we are very thorough and very rapid about our response to it. “You can say the impact is on quality, but it’s a pest. You can’t control it, and it competes with your rice yields.” The confirmation of red rice in an Artois, Calif.-area field this summer was made after a pest control advisor brought a sample of suspicious plant material into the Glenn County Agriculture Commissioner’s office. The PCA thought it might be Bakanae, or foolish seedling disease. The Artois field is the only find so far, but agricultural officials are asking growers and PCAs to report anything they suspect might be red rice to their local ag commissioner, farm advisor or California Crop Improvement Association. “If they see anything out there that looks like a rice plant that’s really tall, they should get somebody to identify it,” says Robert Birdseye, an environmental biologist with the Glenn County Agriculture Commissioner’s office. “[Red rice] grows as tall or taller than the late watergrass, or mimic, except it has very pronounced long, white awns.” Because red rice is the same species as commercial rice—Oryza sativa—the California Department of Food and Agriculture currently does not consider it a pest and is therefore not able to quarantine infested fields or enforce eradication measures. “There are no repercussions [to reporting it],” Birdseye says. “All we want to do is find out where it is and help the growers clean it up.” This is not the first time California rice growers have had to contend with red rice, either. The state battled it in the 1950s but were able to eradicate it through diligent control measures and widespread use of certified seed. How can I tell red rice? Red rice looks like commercial rice only much taller–4 to 5 feet tall. In fact, it can be as tall as late watergrass, or mimic. Red rice also has pronounced, long, white awns that have been removed through breeding from most California commercial varieties. When you rub the leaf toward the stem, red rice is very rough—almost abrasive—compared to most of the smoother-leafed commercial varieties. The name red rice may be misleading in terms of identification. “It doesn’t show red bran until it’s almost mature,” Birdseye says. “When it’s in the dough stage or coming out of the dough stage, it will look like regular rice. “When it’s mature, the shell is very red in color and it shatters very easily.” Red rice also is vigorous and can have as many as seven to eight tillers on one plant. In the Artois field, Birdseye says the red rice was slightly greener than the M-202 and became even more conspicuous as the commercial rice began drying down. If red rice is allowed to become established, it could become a quality concern. The U.S. Department of Agriculture grade standards allow up to 0.5 percent red rice and/or damaged kernels in rough rice to be called U.S. No. 1. Control recommendations How the red rice came into the field remains a mystery. “We talked to the people who seeded the field and found out what other varieties they seeded,” Birdseye says. “I looked at the fields in Glenn County, and there was nothing in those fields. CCIA is looking into the possibility that the certified seed was contaminated some way.” The University of California Cooperative Extension office is working with the grower to develop a plan to control the red rice. “These are just recommendations, but the grower seems to be pretty interested in what he can do to get rid of it, and hopefully he won’t have to see it again,” says Chris Greer, farm advisor for Glenn, Tehema, Colusa and Yolo counties. During the 2003 season, Extension recommended the grower rogue the
red rice plants from the field. Unfortunately, Greer says, some of the
seeds had already shattered on the ground. UC also emphasized equipment
sanitation to ensure the seed wasn’t moved to other fields on equipment,
such as combines. During spring 2004, UC is encouraging the grower to fallow the field and treat the spring weed flush with glyphosate herbicide. During the summer, they are recommending he flush the field to encourage red rice germination and spray again with glyphosate. Greer is proposing a couple of different options to the grower for subsequent seasons. One would be to rotate to a different crop, such as alfalfa, which is already grown in the area. Rotating to a permanent crop would allow the grower to use grass herbicide to control any red rice that might germinate, Greer says. And having a crop in the ground for about four years would address some of the seed dormancy issues associated with red rice. If the grower opts to return to rice, Greer is recommending he leave the three infested checks fallow. In the other checks, he could plant a short-season smooth-leafed variety and maintain a flood with no draining. By planting an early-maturing rice, Greer says the grower could avoid having both the commercial rice and any red rice plants heading at the same time. Planting a smooth-leafed variety would aid in roughing. And maintaining a permanent flood helps suppress red rice germination. Contact Vicky Boyd at (209) 571-0414 or vlboyd@att.net. Internet Hotlinks: Rice diseases in Arkansas Missouri rice disease control Louisiana State University AgCenter rice diseases LSU Rice Varieties and Management Tips LSU Plant Disease Control Guide—Rice
|
|