Mild weather in August boosts final rice crop

Few in the big crowd at Rice Field Day this year at the Biggs, Calif., Rice Experiment Station would argue with the state's 2006 crop estimate of 7,700 pounds per acre.

And most are thankful it is not lower after the three-week delay in planting and a searing July hot spell.

A 78-sack state average would not get too much of an argument and one “yield expert” thinks the state could make an 8,000-pound average. Only the bold would go that far now.

Regardless of the number you pick, growers are willing to take a crop in the 77-80 sack range. It has been that kind of year. No record, but not bad considering.

Brothers Bill and Wayne Vineyard, Placer County, Calif., rice growers near the town of Lincoln, are happy to admit to a good crop. No bin buster, but considering the late start and extreme July heat, they were pleased at Rice Field Day with results.

It was the mild August weather that made the difference for the Vineyards, according to Bill. “That is what really filled the heads,” he said.

However, the crop is a bit taller than Wayne likes.

“There is no lodging yet, but the water is still on it,” he said.

Asked if the excessive heat caused any blanks, Bill said, “We have blanks every year. If we had no blanks, we'd have a heckuva crop.”

University of California Cooperative Extension rice farm advisor in Butte County, Randall “Cass” Mutters, said two things cause blanks: hot and cool weather. “There will be no cool weather blanks this year,” he said.

Mutters agrees that it will be a good year for California rice growers.

“There are some very nice looking fields, but there are also some real dogs and those will drag the average down.”

While the Vineyard brothers believe the mild-August filled heads, Mutters believes it improved quality. “When you get the kind of August we have had, quality is usually very good.”

Mutters also agrees with Wayne Vineyard that lodging before harvest is a valid concern.

“There is a field of Japanese rice not far from the field station that is almost completely laying down and the water is still on it,” he said.

The '06 rice plants are generally taller than normal due to longer internodes put on by plants after the hot spell. If the '06 California rice crop is to make an 80-sack average, it may take skilled head lifted harvesting.

Mutters said the crop has pretty well caught up to normal and he expects harvest to start by mid-September.

For growers and PCAs who were hoping the late start would cut into the rice water weevil (RWW) population, there's no such luck. University of California entomologist Larry Godfrey said about three times more RWW were trapped this year compared to last year.

Godfrey said RWW populations cycle and,“We appear to be on an upswing from the past and some fields were hurt by weevils this season.”

Fortunately, rice growers were given good control materials in pyrethroids after the loss of Furadan in 2000. Warrior was the first pyrethroid and it was followed by the registration of Mustang and Proaxis, two other pyrethroids.

These materials are applied at the 2-to three-3 stage rather than the pre-plant stage for Furadan.

“The industry has effectively used these new pyrethroids for the past five years and they are now part of the common pest management scheme,” said Godfrey. In 2004, the most recent year data is available, 80,000 acres were treated with pyrethroids.

More than 90 percent of all insecticide usage in rice is a pyrethroid insecticide. Dimilin and Sevin were the only other insecticides used in rice in any significant quantities in 2004.

The bad news is that pyrethroids are coming under the regulatory microscope because they bind tightly to organic matter and have the potential to run-off fields and into waterways where it may kill several aquatic organisms.

Pyrethroids have been found in surface water and stream bed sediments, said Godfrey, who added regulatory agencies are assessing the situation. Godfrey told the 200 growers and PCAs at Rice Field Day that pyrethroids use could become restricted.

This is why Godfrey is looking at alternatives. He has found some.

There are several experimentals being testing, but their registration is not imminent, said the entomologists.

However, there are some insecticides registered on crops in the United States and Japan that have been promising in Godfrey's trials.One is etofenprox, a product registered on several crops in Japan. It is marketed as Trebon by Mitisui Chemical. It is classified as a pyrethroid, but it differs from current pyrethroids chemically.

Tested in ring plots for the past two seasons, etofenprox provided more than 90 percent control of RWW larvae when applied at the 3-leaf stage. It was not effective pre-flood.

The compound received a Section 18 registration in Louisiana this season. It was justified due to the loss of Icon seed treatment and the reduced hazard of Trebon to crayfish compared to pyrethroids.

Another compound that provided excellent control in ring tests was indoxacarb. It is sold as Steward and Avaunt by DuPont Agricultural Products in crops other than rice. It is not registered for use on rice.

It is in the oxadiazine class of insecticide. It has a low degree of toxicity on non-target anthropods as well as user/applicators.

Godfrey applied it at the 3-leaf stage at 0.11 pounds a.i. per acre and it provided excellent RWW control. The feasibility of registering it on rice with the assistance of the IR-4 program is being investigated.

Several neonicotinoid insecticides have been evaluated for RWW control. One was ineffective. Another was not registered due to registration limitations. However, one, clothianidin, was evaluated for the past two seasons as pre-flood and 3-leaf stage of the crop and as a seed treatment this season.

Godfrey said it was “highly effective” in '05. “This material appears to have an excellent fit in the rice system for RWW control and development efforts are proceeding.”

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