University of California Cooperative Extension farm advisor Franz Niederholzer, an orchard systems expert involved with tree nuts and navel orangeworms, is finding “massive losses” in at least four counties due to a major infestation. “The picture is not yet totally clear, but NOW damage has been heavy, particularly in the Western Sacramento Valley in Glenn, Colusa, Yolo, and into Sutter counties. These places were hard hit by frost and freeze that virtually wiped out some growers. There was no crop. There was no money for sanitation, removing old nuts, and that signaled a massive ‘stop on by’ invitation to the navelworm population.”

“This may be the worst worm damage, historically, in the last 20 years,” Niederholzer says, “topping that of other 21st century NOW episodes. Part of the story centers on economics, specifically because cost of clean-up produced limited (or lack of) sanitation area wide that encouraged a huge pest population…one you can’t spray your way out of because of its size."

Source - https://www.freshplaza.com