Unique pests for a unique production system: Past and recent arthropod issues in California rice

California is the second largest rice producing state in the US with half a million acres in production annually. The rice water weevil, a key pest of the southern US, was introduced into California in the late 1950s, becoming a pest of concern during several decades. Recently, the importance of this pest has declined considerably. In the water seeded system practiced in California, the tadpole shrimp is the key pest. Tadpole shrimp is a crustacean that can reduce stand establishment by feeding on seeds while they germinate. While this pest is unique to California, it has the potential to move to other production areas where water seeding is practiced. The armyworm is an occasional pest that can cause severe defoliation and panicle injury during outbreaks. Recent moth trapping data seem to indicate that this pest migrates into the rice production area of California every year. Field observations and studies that highlight the arthropod pest dynamics in California and efforts to improve management will be discussed.