Statement of Problem: Invertebrates, such as the Rice Water Weevil (Lissorhoptrus oryzophilus), tadpole shrimp (Triops longicaudatus), seed midge (Crcotopus sylvestris), armyworms (Spodoptera praefica and other species) and other species, can severely damage rice and cause up to a 30% yield loss on the 500,000 acres of rice in California (losses in the 10% range are more common). Research in my lab has investigated several cultural control methods that aid in Rice Water Weevil control. Insecticides are the primary means used by growers to control this pest and this is a concern given the aquatic nature of rice production and the proximity to the Sacramento River waterway system. My lab has been developing refined management strategies for this pest. Over the last ~10 years, post graduate researchers, staff research associates, and graduate students have been involved in this research. Kevin Goding is coordinating this work, as a staff research associate at this time. UC Cooperative Extension Rice Farm Advisors have assisted in the work as well as the Rice Experiment Station.
Examples of Work during Recent Years
- Improved control strategies for Rice Water Weevil, especially reduced risk insecticide materials including biological insecticides.
- Effects of cultural control measures such as winter flooding, date of seeding, rice varietal differences, etc., on Rice Water Weevil populations and damage potential.
- Implications and research needs associated with switching from a preventative insecticide method of control to an "as needed" technique for Rice Water Weevil.
- Damage thresholds for Rice Water Weevil have been studied.
- Rice plant response, physiological and defensive, was studied.
- Influence of insecticide applications on populations of invertebrate nontargets in rice fields.
- Studies on tadpole shrimp biology and management
- Investigations on the incidence of biological control of armyworms in rice
- Studies on possible insect causes of "pecky" rice, i.e., damaged kernels, which has been seen at low levels in some areas in recent years.