UC Rice Blog

Over the past year, weedy rice has become a top issue in California rice, both for individual growers and for the industry as a whole.

I went out on a few farm calls in the past week, and have noticed a trend. Due to the unusually wet weather this spring, some of the weeds are already producing seed out in the field! This occurs when the field was moist or wet in the spring, and was not tilled or sprayed prior to planting.

I have received reports of significant defoliation due to armyworms from several areas: Glenn, Colusa, Butte and Yolo counties. In most areas the defoliation is severe but the area affected within fields still small. I inspected a field in Glenn County.

Moth numbers have increased since the week of June 12, specially in the Colusa trap. The degree day model predicted worms in the fifth instar by June 22; I'm starting to receive reports of worms in Colusa, Glenn and Butte counties.

The number of moths trapped has increased in all locations, except in the North Sutter one (which was already high to begin with). In most fields the rice is still in the three to five leaf stage.