UC Rice Blog

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.

Number of moths trapped per day is increasing. Numbers are higher in areas where crop diversity is higher. I haven't seen any worms yet, but they are expected by the end of the month. At this point, moths may be mating and laying eggs on weeds and other plants in the area, including rice.

Grow Rice? Help Birds! Rice provides livelihoods and food for people and places to rest and feed for many birds, too. Small changes to field management can increase the value of rice fields for the birds that use it.