A Collaborative Approach to Integrated Pest Management of Tadpole Shrimp in California Rice Fields.

• 2016 annual report

Commodities

Practices

Tadpole shrimp (Triops longicaudatus; TPS) is a vernal pool crustacean, native to the western hemisphere. Historically, population levels were tolerable and seldom caused economic damage in rice. However, over the past decade TPS has become an increasingly significant pest for California rice growers. TPS feeds on and uproots young seedlings and its swimming and burrowing habits increase the suspended silt in flooded fields and disrupt the photosynthetic capacity of the young rice seedlings. TPS eggs can remain dormant for ~20 years or more (Brendonck and Meester, 2003). This evolutionary adaption could be key to the recent population explosion of TPS in California rice. By characterizing the spatial distribution of TPS eggs (eggs in diapause vs active eggs) through sampling farmers’ fields and analyzing TPS egg frequencies using geostatistical technique kriging, we can develop effective monitoring techniques. Eggs recovered from farmers’ fields are photographed using hyperspectral imaging to distinguish between diapause and active eggs. Using hyperspectral technology we can subsequently quantify changes in this ratio under various treatments, such as resource availability, temperature, and dissolved oxygen throughout the adults’ lifespan.

1. 1. To determine aggregation pattern of TPS eggs in rice fields using kriging and spatial analysis by distance indices (SADIE). (Summer 2016 & 2017).
      1. 1. This will allow farmers and researchers to develop an efficient sampling system to monitor and evaluate TPS populations annually and react with the appropriate management techniques. Ultimately facilitating the evaluation of management practices on TPS egg bank.

1. 1. Characterize TPS egg diapause and hatching patterns using hyperspectral imaging techniques. (Summer & Fall 2016).
      1. 1. This could be useful in predicting future TPS outbreaks once a monitoring technique has been devised.

1. 1. Understand changes in TPS egg bank by characterizing factors that affect egg survival or alter diapause ratio. (Winter, Spring & Summer 2017).
      1. 1. The factors identified could be exploited to increase egg mortality and reduce egg bank.

1. 1. Evaluate the effects of cultural management practices (i.e. straw burning, straw incorporation, tillage practices, irrigation regimes, and fertilization patterns) (Summer 2016, 2017, & 2018).

1. 1. Explore alternative insecticide modes of actions emphasizing biorational and biological products that can effectively reduce TPS populations with minimal cost and impact on the environment. (Summer 2016 & 2017).

1. 1. Work together with the farmers, extension specialists, and researchers cooperating in this project to disseminate findings and management strategies to other rice growers and pest control advisers through field days, grower workshops, newsletters, and workshops. (Fall & Winter 2017).