Armyworms threaten crops in Modoc County. The Devil’s Garden Research & Education a University of California Cooperative Extension in Modoc County, based in Alturas, is warning largely alfalfa growers to be on the lookout for armyworms in your small grains and grass pastures. In 2017 a large infestation impacted the local counties including Lassen and Modoc. In the most extreme of cases when the number of armyworms is high enough fields can be wiped out, as what occurred in the fall of that year. Many growers lost their third cutting or fall grazing ground to infestation. Armyworms can be treated when they are young but are almost impossible to treat when larger. In the larvae stage, they can consume an estimated 80 percent of the total plant matter within the last 4 days of feeding. Monitoring early, as the worms are active before the light of the day, and often can help you to mitigate their populations. The Devil’s Garden Education and Research cooperative say while there is no economic threshold for pasture and grasses in California, other states recommend treatment after worm populations exceed typically 2-4 larvae/square foot. You can visit the UC ANR website for a detailed look at crop thresholds and mitigation practices.
