- Author: Kathy Keatley Garvey
Agricultural entomologist and Cooperative Extension specialist Ian Grettenberger of the UC Davis Department of Entomology and Nematology and his colleagues propose alternative management.
Grettenberger's poster, “Past Pyrethroids: Alternative Management Approaches for Tadpole Shrimp in Rice,” presented at Entomological Society of America meeting (Oct. 31-Nov. 3) in Denver, offers non-pesticide alternatives, including the use of mosquitofish.
Collaborative research with UCCE Butte County director and Rice Farming Systems Advisor Luis Espino and UC Davis staff research associate Kevin Goding, indicates that mosquitofish proved able to suppress shrimp populations.
“Tadpole shrimp (Triops longicaudatus) are an early-season pest in California rice,” Grettenberger explained in his abstract. “Soon after flooding, eggs hatch and growing shrimp are soon large enough to damage germinating rice seedlings. Currently, pyrethroid insecticides are heavily relied upon for management, as they are in many cropping systems, because of their efficacy and low cost. However, contamination of surface waters is a concern, as is insecticide resistance.”
"We evaluated alternative management strategies that could be used to manage tadpole shrimp,” he wrote. “We tested a number of materials using small metal ring plots and natural shrimp populations. This included several timings of applications to mimic an early, more proactive application along with a later, rescue application, as well as reduced rates of a number of insecticides.”
Deep Look Video. Tadpole shrimp recently made the national news in two ways, Grettenberger said. First, they made news with the sudden appearance of tadpole shrimp following monsoon rains this summer in an ancient ceremonial ball court at the Wupatki National Monument in northern Arizona (https://www.livescience.com/dinosaur-shrimp-emerge-arizona). In October, KQED's Deep Look released a new video, “Tadpole Shrimp Are Coming For Your Rice," the work of lead producer and cinematographer Josh Cassidy and other members of the Deep Look crew. (See https://youtu.be/T2xnXaX7r3g.) Grettenberger assisted with the project, providing tadpole shrimp and taking some of the video clips used in the five-minute video.
“Much of his shooting was in my garage,” the UC Davis entomologist said, “so I get to see just how much effort and care goes into producing these videos. They end up pretty short, but that doesn't mean it is simple to get all the pieces together.”
“This tadpole shrimp is coming for your rice,” the narrator said. “Hungry hordes of them find their way into the ice fields of California's Central Valley and go to town munching on the young seedlings. But where did they come from, with the ocean so far away? A couple of weeks ago, this was just a dry dusty field. Turns out they were here all along.”
Deep Look referred to them as “time travelers,” as the eggs of shrimp tadpoles can be viable for decades and hatch when the rice growers flood their fields. "At the very least, they have survived as eggs since last season," Grettenberger noted.
The pests are neither tadpoles or shrimp but are fresh-water crustaceans descended from the ocean. “They look like tiny horseshoe crabs,” Grettenberger told Deep Look. “It's obvious when rice fields have lots of tadpole shrimp in them, because they stir up the mud making the water look a bit like chocolate milk. There will also be shrimp zooming around, many upside down at the surface, popping up for a few seconds before disappearing back into the murkiness."
Adult tadpole shrimp cannot survive when the soil dries out. But Grettenberger said their eggs have a rugged outer layer called a “chorion” that protects the eggs from desiccation.
“They've been living this way for hundreds of millions of years-- since before the dinosaurs-- waiting out droughts, changing climates, even global catastrophes,” KQED relates in the video. “In a world where the future is unpredictable, tadpole shrimp are the ultimate survivors.”
Grettenberger, who joined the UC Davis Department of Entomology faculty in January, 2019, focuses his research on field and vegetable crops; integrated pest management; applied insect ecology; and biological control of pests.
Additional Information:
- Resource on tadpole shrimp, UC Statewide Integrated Pest Management Program (co-authors, the late Larry Godfrey, UC Davis Department of Entomology and Nematology; Luis Espino, UC Cooperative Extension; and Sharon Lawler, UC Davis Department of Entomology and Nematology
- "Effect of Rice Winter Cultural Management Practices on the Size of the Hatching Population of Triops longicaudatus (Notostraca:Triopsidae) in California Rice Fields" (Co-authors Larry Godfrey,
- Author: Kathy Keatley Garvey
Long will receive the award at a presentation at 4:30 p.m., Tuesday, May 28 in the Alpha Gamma Rho Hall (AGR) room of the Walter A. Buehler Alumni Center. A reception begins at 4.
The award, established in 2008, honors individuals who exhibit the leadership, work ethic and integrity epitomized by the late Eric Bradford, a livestock geneticist who served UC Davis for 50 years, and the late Charlie Rominger, a fifth-generation Yolo County farmer and land preservationist.
The award presentation prefaces the Agricultural Sustainability Institute's Distinguished Speakers' Seminar, “Building a Better World, the Opportunity to Achieve Climate Drawdown and a Safe Future" by environmental scientist Jonathan Foley, executive director of Drawdown. Foley, ranked by Thomas Reuters as among the top 1 percent of the most cited global scientists, will address the crowd from 5 to 6 p.m.
Rachael Long, a native of Berkeley, received her master's degree in entomology from UC Davis in 1987, studying with major professor James R. Carey. She also holds a bachelor's degree in biology from UC Berkeley, where her father was a biology professor.
Long accepted a position as a pest management, low input systems UCCE advisor for Yolo, Solano and Sacramento counties in 1992. This was one of the first sustainable agricultural adviser positions within UC Agriculture and Natural Resources (UC ANR), with a focus on developing programs to manage pests in field crops with minimal impacts to the environment.
When she started her projects 27 years ago, her ideas were considered “way outside the box and on the fringe,” she recalled. Now her work is mainstream with the UC Integrated Pest Management Program (UC IPM) guidelines incorporating the value of habitat planting for enhancing natural enemies and pollinators on farms for better pollination and biocontrol of crop pests.
The farm adviser is known for her research and advocacy of hedgerows, her leadership in teaching others about agriculture, and her drive to mesh farming, food production, and wildlife conservation. As a result of her work, the California Healthy Soils Initiative and Natural Resource Conservation Service established cost share-funding for hedgerow establishment on farms, for pest management and carbon sequestration.
Long's research focuses on enhancing natural enemies for better biocontrol of crop pests. "Hedgerows are important for enhancing beneficial insects, including bees and natural enemies, for better biocontrol and crop pollination in adjacent field crops, with measurable economic benefits," she says. "Hedgerows can pay off after 16 years for pest control and seven ears if pollination benefits are added in for bees. Bats and birds associated with habitat likewise have economic benefits for helping to control key codling moth pests in walnut orchards."
Long, who worked closely with Charlie Rominger, commented: “I think Charlie would have been excited by this work. When I first started my job, we spent time in the field looking at field edge habitat and all the birds and beneficial insect activity and wondered about their benefits to crop production. Now we know! Lots of positive ecosystem services associated with habitat! Eric Bradford would have likewise been impressed with work that involved 20 plus years of meticulous research work by strong teams committed to data collection, to document the benefits of field edge habitat to agriculture.”
She and her colleagues have published 14 peer-reviewed papers on hedgerow research. Her work, with colleagues Kelly Garbach of Point Blue Conservation Science, and Lora Morandin of the Pollinator Partnership, can be summarized in their research article, "Hedgerow Benefits Align with Food Production and Sustainability Goals," published in September 2017 in California Agriculture. Her most recent paper appeared in UC ANR's special global food initiative edition of California Agriculture.
In addition to her research, Long has delivered hundreds of presentations about the importance of hedgerows on farms; conducted and published surveys on how to better reach out to the grower community to enhance the adoption of hedgerow plantings, as well as the importance of bats, birds, and raptors on farms; and has mentored many undergraduate and graduate students.
Long brings teams of researchers together to work on projects focusing on agriculture and ecosystem services, which lead to enhanced conservation on farms. In 2013, she and her colleagues received the California Department of Pesticide Regulation IPM Innovator Award for work on hedgerows and pest management. She was also a pioneer in developing practices for protecting water quality from non-point source pollution from agricultural runoff in the early 2000s.
For reservations to the May 28 event, access this website.
- Author: Kathy Keatley Garvey
Niño is the first of six speakers at the workshop, which begins at 1 p.m. and continues through 3:30 p.m.
Pollination is important for a number of crops grown in Colusa County, said workshop coordinators Katharina Ullmann of the Xerces Society and Farm Advisor Rachael Long, Yolo County Cooperative Extension Office. At the Crop Pollination Workshop, regional experts will share the latest on honey bee health, onion pollination, management practices that support pollinators of cucurbits and almonds, and how to encourage beneficial insects on your farm using hedgerows.
The workshop also will provide information on Natural Resources Conversation Service (NRCS)-funded conservation cost-share programs, such as those supporting hedgerow establishment.
The event is free and open to all interested persons. No reservations are required. Sponsors include UC Cooperative Extension (UCCE) Xerces Society, UC Davis, UC Berkeley, Colusa County Resource, and UC Agricultural and Natural Resources.
Niño's presentation is from 1:05 to 1:25. The complete schedule:
1 p.m. Welcome
1:05 p.m. "Multiple Stresses Impact Honey Bees" by Elina Niño, UC Davis Department of Entomology and Nematology
1:25 p.m. “Insecticides Reduce Honey Bee Visitation and Pollen Germination in Hybrid Onion Seed Production” by Rachael Long, Farm Advisor, UCCE, Yolo County
1:50 p.m. “Best Management Practices for Squash and Pumpkin Pollinators” by Katharina Ullmann, Pollinator Conservation Specialist, Xerces Society and formerly of UC Davis (she received her doctorate in entomology last year)
2:15 p.m. “Enhancing Habitat in Almonds and Almond Pollination” by Kimiora Ward, staff research associate, UC Davis Department of Entomology and Nematology
2:40 p.m. “Hedgerows Enhance Pollinators and Pollination Services” by Lauren Ponisio, graduate student, Environmental Sciences and Policy Management, UC Berkeley
3:05 p.m. “Hedgerows Enhance Biodiversity and Provide Crop Benefits in Agricultural Landscapes” by Rachael Long, Farm Advisor, UCCE, Yolo County
3:20 p.m. “USDA-NRCS Financial and Technical Support for Hedgerows,” Andrea Casey, Colusa NRCS DC
For more information, contact Long at (530) 666-8734 or rflong@ucanr.edu.
