Japanese millet is not a weed of rice in our area. However, a PCA recently noticed it in an organic rice field. Japanese millet is in the same genus as our common watergrasses, and looks similar, but is much more robust. It seems to grow well under flooded and dry conditions.

The presence of this plant in the organic rice field was puzzling. Then the PCA learned that the field had been in pasture the year before. Most likely, the Japanese millet was part of the mix of grasses seeded as pasture and produced seed that survived the winter and germinated in the flooded rice field. 

Unusual find, hopefully we won't see it ever again!

RICE FIELD DAY

 Wednesday, August 28, 2013

Rice Experiment Station, Biggs, CA

The annual Rice Field Day will be Wednesday, August 28, 2013, at the Rice Experiment Station (RES), Biggs, California. You and your associates are cordially invited to join us for this event to observe and discuss research in progress at RES. Rice Field Day is sponsored by the California Cooperative Rice Research Foundation (CCRRF) and University of California (UC), with support from many agricultural businesses. Following is a brief outline of the Rice Field Day program (updated program here).

7:30 - 8:30 a.m. Registration

Posters and Demonstrations

8:30 - 9:15 a.m. General Session

CCRRF Annual Membership Meeting

D. Marlin Brandon Rice Research Fellowship

California Rice Industry Award

9:30 - Noon Field Tours Of Rice Research

Variety Improvement

Disease Resistance

Insects and Control

Weeds and Control

Noon Lunch

The program will begin at 8:30 a.m. with a General Session that serves as the Annual CCRRF Membership Meeting. Posters and demonstrations will be in place during registration until after lunch. Field tours of research will emphasize progress in rice variety improvement, disease, insect, and weed control. The program will conclude at noon with a complimentary lunch that includes rice. The RES is located at 955 Butte City Highway (Hwy. 162), approximately two and one half miles west of Highway 99 north of Biggs, California.

This is the first time since I moved to California that I've seen leafhoppers actually injuring rice. Leaf tips turned yellow, and from the road it looks like salt injury, but once you get in the field you can see leafhopper nymphs and adults jumping and flying around.

What we have is aster leafhopper. They are reported to feed on broadleaf weeds and rice. I have some research plots in this field, with some areas where rice was not planted between plots. Weeds grew on the open areas, and after a propanil application that killed the weeds the leafhoppers might have moved to the rice.

From the UC IPM: Rice website: "Although leafhoppers can be present in fields during most of the growing season, the heaviest populations usually occur from early July through mid-August. Leafhoppers feed on rice plants by sucking up plant fluids through their long, piercing mouthparts. Although they are not known to vector of any rice pathogens in California, leafhoppers may occasionally occur in sufficient numbers to cause damage by their feeding. Injury associated with leafhoppers include stippling, yellowing, and drying leaves. Leafhoppers prefer senescing leaves, and symptoms usually occur on older leaves first. Leafhoppers are very mobile; adults fly and nymphs jump. Thus, infestations are rarely localized but appear generally throughout the field."

We haven't treated this field yet. There are still plenty of leafhoppers, but the plants are growing fast and putting out new leaves. If the leafhoppers remain and start injuring the flag leaf, a treatment might be appropriate.

I've been getting calls about sedge surviving propanil applications. Last year, research conducted by Albert Fischer showed that there are populations of smallflower umbrellasedge that are truly resistant to propanil (read the article here). However, just because sedge was not controlled by propanil, it doesn't mean it is resistant. Some other explanations for lack of control are:

• Propanil was applied too late. The older the weeds, the harder they are to kill.
• The rice canopy was large and shielded the weed during the application.
• Water level was too high and weeds were not exposed.
• Incompatibilities in the tank mix.
• Dosification errors.
• Equipment failure.

If you suspect you have propanil-resistant sedge in your field, the UC Rice Weed Project can test seed from the suspected weeds and confirm or rule out resistance. Collect a seed sample, fill out the Resistant Weed Seed Testing form (download it here), and send or drop off the sample at the Rice Experiment Station in Biggs. The testing is conducted early in the spring and the results made available to you ahead of seeding.