Wednesday, December 17, 2014
YOLO COUNTY NEWS
99 CENTS

Mosquitofish form first line of defense against pests

MosquitoFish1w

Luz Rodriguez, a staffer at the Sacramento-Yolo Mosquito and Vector Control District, looks at thousands of mosquitofish swimming in a pool at the district's facility in Elk Grove, the biggest breeding ground in the world for the mosquito-loving fish. Sue Cockrell/Enterprise photo

By
From page A1 | June 20, 2014 |

The Sacramento-Yolo Mosquito and Vector Control District wages battle against mosquitoes, defending rural and urban populations from a long list of debilitating diseases. And its No. 1 weapon against the deadliest pest on Earth?

Fish.

Specifically, Gambusia, silver and pinky-finger-sized, that feast on mosquito larvae and other water-laying insects.

The district’s Elk Grove facility is the biggest breeding ground in the world for mosquitofish, as they have been aptly nicknamed; 2.7 million on average are born, grown and deployed each year. “Planting” the fish means fewer pesticides and less manpower are needed to control mosquito populations.

Every day from April to August, field agents load their pickups with 150-gallon fish tanks and deliver the mosquitofish free to rice paddies, abandoned swimming pools and backyard ponds.

A decade or so ago, they tried to drop Gambusia into flooded rice fields from a crop duster, usually used to spread pesticides or seed. It flew as close to the ground as it could, but at 180 miles per hour.

Seventy percent of the fish died, said Tom Hedley the fisheries supervisor.

So, no more airplanes. Technicians now scoop the fish up out of the tank in a net, kneel down and place them gently in the water.

“We try to traumatize them as little as possible,” Hedley said.

Elk Grove houses the biggest mosquito fishery in the world because of the high concentration of rice growers in the Sacramento Valley. The dual-county district was formed when scientists realized that many of the mosquitoes plaguing urban Sacramento were buzzing over from Yolo County.

Then, people were concerned about culix mosquitoes, said Robert Washino, a mosquito expert, professor emeritus at UC Davis and retired 38-year-old trustee of the vector control district. In 1952, the Central Valley suffered an encephalitis outbreak that killed 50 people. Now, folks worry about West Nile virus: So far this season, Yolo County has counted one infected mosquito and four infected birds — three of which were found in Davis.

“And in the last 10 years, we’ve seen the introduction of the aedes mosquitoes, much more urban mosquitoes,” Washino said.

Recently found in the Bay Area and Los Angeles, aedes aegypti mosquito worries public health officials because it can spread dengue and chikungunya viruses. Fish aren’t as effective in cities and neighborhoods, so vector control officers rely more heavily on traps set around the two counties.

Mosquitoes caught in the trap are taken back to the lab in Elk Grove, where they are examined and tallied on a colorful analog machine that resembles a two-tiered children’s xylophone. If the mosquito is a species known to carry West Nile, lab techs grind it into a paste and test for pathogens. Chemicals are deployed only when viruses are found.

Down the hall from the lab, the district raises mosquitoes in addition to fish. The insectary is a stifling, moist room, like summer in Georgia, with white rusting trays full of warm water and, terrifyingly, thousands of mosquito larvae. They look like little sticks, like little dandelion seeds wiggling around in the water, searching for bits to eat so they can grow big, pupate and suck your blood (or that of birds or horses or other animals). Researchers will use them to test pesticide resistance or as learning instruments in classrooms.

But with schools on break, the vector control technicians are in the field full time, delivering hungry fish to still water to gulp down mosquito larvae and keep disease at bay.

— Reach Elizabeth Case at ecase@davisenterprise.net or 530-747-8052. Follow her on Twitter at @elizabeth_case

Comments

comments

Elizabeth Case

  • Recent Posts

  • Enter your email address to subscribe to this newspaper and receive notifications of new articles by email.

  • .

    News

    GPAS and test scores up for UCD’s newest undergrads

    By Julia Ann Easley | From Page: A1

     
    Million Cat Challenge aims to rescue shelter felines

    By Pat Bailey | From Page: A1 | Gallery

     
    Everest visit fulfills judge’s lifelong dream

    By Lauren Keene | From Page: A1 | Gallery

    Supervisors remove Saylor from First 5 Yolo Commission

    By Anne Ternus-Bellamy | From Page: A1

     
    Water officials fret over rain’s effects

    By The Associated Press | From Page: A2 | Gallery

    Bob Dunning: Not enough hours in the month

    By Bob Dunning | From Page: A2

     
    Fatal Capay crash leads to driver’s arrest

    By Lauren Keene | From Page: A2

    U.S., Cuba seek to normalize relations

    By The Associated Press | From Page: A2

     
    Donate to STEAC at Original Steve’s

    By Enterprise staff | From Page: A3

    Beer and film tour boosts bike group’s coffers

    By Enterprise staff | From Page: A3

     
    Yolo Crisis Nursery in full swing

    By Special to The Enterprise | From Page: A3

     
    Creative women share food, friendship

    By Enterprise staff | From Page: A3

    Pedal around Davis on weekly bike ride

    By Enterprise staff | From Page: A3

     
    Overeaters get support at meetings

    By Enterprise staff | From Page: A4

    Fibro Friends will update their journals

    By Enterprise staff | From Page: A4

     
    Input sought on county’s facility needs

    By Special to The Enterprise | From Page: A4

    Traditional carols service is Saturday at St. Martin’s

    By Enterprise staff | From Page: A4

     
    Have coffee with the mayor on Friday

    By Enterprise staff | From Page: A4

    Stockings brighten holidays for special kids

    By Enterprise staff | From Page: A4 | Gallery

     
    Evening tai chi classes start Jan. 6

    By Enterprise staff | From Page: A4

     
    Name Droppers: Law prof earns peace prize for nonfiction

    By Enterprise staff | From Page: A5 | Gallery

    Community menorah lighting set Wednesday

    By Enterprise staff | From Page: A5

     
    Latest immunization data shows little improvement locally

    By Anne Ternus-Bellamy | From Page: A5

    School board will vote on repairs, new portables

    By Jeff Hudson | From Page: A6

     
    Study: National monument could boost local economy

    By Special to The Enterprise | From Page: A6

    Round up at the registers for Patwin

    By Enterprise staff | From Page: A7

     
    Parent/toddler art and music program offered

    By Enterprise staff | From Page: A7

    Libraries will be closed around the holidays

    By Enterprise staff | From Page: A7

     
    Cloudy — yet safe — tap water adds to negative health effects

    By Special to The Enterprise | From Page: A7

    Come Worship with Us

    By Special to The Enterprise | From Page: A10

     
    .

    Forum

    This ought to teach her love

    By Creators Syndicate | From Page: B5

     
    Defying Western academic norms

    By Letters to the Editor | From Page: A8

    Boycotters are our future profs

    By Letters to the Editor | From Page: A8

     
    Many thanks to The Avid Reader

    By Letters to the Editor | From Page: A8

    Language failed me that night, but not now

    By New York Times News Service | From Page: A8

     
    Steve Sack cartoon

    By Debbie Davis | From Page: A8

    Grand jury function clarified

    By Letters to the Editor | From Page: A8

     
    .

    Sports

    UCD reveals a challenging softball schedule

    By Enterprise staff | From Page: B1 | Gallery

     
    Tumey talks about state of Aggie athletics, where they’re headed

    By Bruce Gallaudet | From Page: B1 | Gallery

    Davis gets Rio Linda as Curry Invitational starts Thursday

    By Bruce Gallaudet | From Page: B1 | Gallery

     
    Sports briefs: Former Aggie Descalso inks deal with Colorado

    By Staff and wire reports | From Page: B8

     
    Westbrook, Durant lead Thunder past Kings

    By The Associated Press | From Page: B8 | Gallery

    .

    Features

    Some vegetables just can’t be beet

    By Julie Cross | From Page: A9 | Gallery

     
    .

    Arts

    .

    Business

    .

    Obituaries

    Rena Sylvia Smilkstein

    By Special to The Enterprise | From Page: A4

     
    .

    Comics

    Comics: Wednesday, December 17, 2014

    By Creator | From Page: B6