UC Blogs
Parasitic wasps battle Asian citrus psyllid
Western Farm Press ran a detailed update on efforts at UC Riverside to identify and release natural enemies of Asian citrus psyllid to aid in the fight against the feared citrus pest and the deadly citrus disease huanglongbing it carries in other parts of the U.S. and world.
To date more than 160,000 parasitic wasps have been released in over 400 locations spanning 350 zip codes, 64 cities and six counties in southern California, the story said. The counties are Los Angeles, Orange, San Bernardino, Riverside, San Diego and Imperial.
“What was remarkable was we had put out few parasites in relatively few areas (and) they survived just fine,” Hoddle said. “They came through their first winter here in southern California with no problem. That is always the first test: can they survive their first winter?”
Hoddle told Fitchette he is encouraged by the success of the program and by the biological success of the wasp. Since it was first released, it has developed its own breeding populations and has been discovered as far as eight miles away from initial release sites, indicating that it is quite mobile.
Hoddle cautions that the Tamarixia, and another parasitoid called Diaphorencyrtus aligarhensis (Encyrtidae), which could be released in California later this year, are not “silver bullets” in the Asian citrus psyllid/huanglongbing fight. Nevertheless, they do offer hope.
Commercial orchards will continue to spray for the ACP, but urban environments can employ biological control measures when the spray program operated by the state is too expensive to continue.
“As long as we maintain well-irrigated urban environments with plenty of citrus in them the Asian citrus psyllid is going to be here to stay,” he said.
Western Bumble Bee Making a Comeback
Incredible. Absolutely incredible. The Western bumble bee (Bombus occidentalis) seems to be making a comeback of sorts in some parts of the...
This Western bumble bee was found on Mt. Shasta on Aug. 15, 2012. (Photo by Kathy Keatley Garvey)
Close-up of Western bumble bee. (Photo by Kathy Keatley Garvey)
Cooperative Extension Educates Public Workers About Aquatic Pests
The Issue
Aquatic invasive species cause significant economic and ecological problems. Quagga and zebra mussels clog water supply systems and deplete plankton; their sharp shells endanger people who work, boat or fish in lakes. Tiny New Zealand mudsnails, which are poor food for fish, displace native snails. Invasive bullfrogs and clawed frogs voraciously consume native species and carry a disease that has decimated native frog populations. Dense mats of invasive waterweeds, such as hydrilla, spongeplant and water hyacinth, slow water flow in streams and irrigation channels, block boats, and kill native species by blocking out sunlight and causing oxygen levels to fall.
However, much of the damage can be reduced if people who work in aquatic habitats are trained. They can help lower the risks of spreading invasive species to new areas and serve as eyes and ears for resource agencies with a mission to manage and control these pests.
What has ANR Done?
In spring 2013, UCCE advisors in Southern California conducted six workshops for 181 staff members of local public works, parks, watersheds and flood control agencies as well as for staff members of a UC Research and Extension Center. The participants learned how to recognize 25 aquatic invasive species, decontaminate their field gear, plan their work to reduce risks of spreading these pests, and report sightings to resource agencies. Forty-nine percent of the participants were minorities and 29 percent were women. Through hands-on exercises, they practiced identifying species, detecting them in mud, inspecting boats and decontaminating boots. The advisors distributed decks of laminated reference cards (with photographs and information), which they created, at workshops. They also wrote blog articles to extend the workshop information widely.
The workshops were supported in part by the USDA Renewable Resources Extension Act and the counties of San Diego, Orange, Los Angeles and Ventura.
The Payoff
The participants significantly increased their ability to identify aquatic invasive species and their environmental impacts, their knowledge of how to report sightings, and their skills on how to decontaminate their gear and avoid spreading these pests. According to survey results, 80 to 90 percent of participants reported learning this information for the first time at one of the workshops. Within the first few following months, agencies reported having made changes. Two agencies implemented new or improved their existing decontamination protocols for field gear and planned their work accordingly to prevent the spread of aquatic pests. Two agencies educated the public on how to prevent the spread of pests by posting signs and talking to visitors at lakes. Five aquatic pest sightings were reported to field supervisors and a New Zealand mudsnail infestation was reported to three natural resources agencies. Altogether, these actions will help to prevent the spread of pests in areas where the workshops were conducted--all 2.5 million acres. More than 14,000 additional people learned about aquatic invasive pests from the advisors' blog articles that were based on their workshops.
"We used the workshop information to modify a permit to prevent a fire-fighting, water-dropping demonstration from spreading quagga mussels from an infested lake to an uninfested stream," said Cathy Nowak, sustainability planner with the Orange County Parks Department.
For more information, contact:
Leigh Johnson (858) 822-7802, ltjohnson@ucanr.edu
Sabrina Drill (626) 586-1975, sldrill@ucanr.edu
Darren Haver (949) 653-1814, dlhaver@ucanr.edu
4-H Million Trees draws close to the halfway point
Started in 2008 by high school 4-H'er Laura Webber, the 4-H Million Trees Project continues to grow and has nearly accomplished half its goal, reported the national TV show EcoCompany. EcoCompany produced a six-minute video (see below) about a group of Woodside teenagers who planted 26 redwood trees in Huddart State Park. The global 4-H initiative, under the auspices of UC Cooperative Extension, is currently at 450,000 trees.
At Huddart State Park, the new trees will help reforest an empty glade that used to be a vollyball court.
"It's a service learning project which is something in 4-H that combines learning with community service," said one of the 4-H team leaders. Fiona Benjamin and Emma Filar are the teen leaders.
The teen leaders involved the Woodside High School Green Academy in the tree-planting event.
"It's good for the environment. It gives us more oxygen to breath," said Karen Estrada, a Green Academy member.
4-H Million Tree planting events have been organized all over the world, including Tanzania, Uganda and Kenya.
"One thing I've taken away from the project is that one person can make an amazing, tremendous difference by getting other people to go along with his or her idea," said the teen leader interviewed in the video.
Spotted Wing Fruit Fly
Last month I wrote a blog about a method of protecting our cherry crop from hungry birds (once we had gotten the upper hand on the Spotted Wing Fruit Fly). Two comments that followed my blog asked about how we were able to protect our Lapin cherries from the darned “cherry maggots”. Hence the topic of this blog!
An excellent management guideline for Drosophila suzukii, aka Spotted Wing Drosophila (SWD) or Spotted Wing Fruit Fly can be found at http://ipm.ucdavis.edu/PMG/PESTNOTES/pn74158.html. Check it out and discover everything you always wanted to know (or maybe not know) about SWD!
This serious pest, originally from Japan, was first found in 2008 in California as it went about damaging RIPENING cherries and berries. Alarming! -given that other fruit flies typically infest rotting or fermenting fruit. Turns out that the female SWD’s ovipositor can saw into unripe cherries and allow her to lay her eggs. Because SWD is a relatively new pest, research about its life cycle and management is ongoing. At present, these are the recommendations which we have followed in our garden, and the results have been good.
Monitoring – Before launching an attack on SWD, be sure that it is actually present in your susceptible trees or berry plants. You can make an effective monitoring trap from a plastic 1 quart yogurt container with a lid. Just drill 10 to 16 holes that are 3/8 inch in diameter around the top part of the container, just below the lid. Bait the trap with 1 to 2 inches of pure apple cider vinegar and a drop of unscented liquid dish soap. Hang a few traps in the shade of your cherry tree or near berry plants in late April or early May, when temperatures have reached 60 to 80 degrees. Check traps weekly or so and look for small drowned male SWDs which have dark spots on the tips of their wings.
Chemical Control – If you find SWD males, consider spraying with spinosad (e.g., Monterey Garden Insect Spray). This insecticide has the least negative impact on the environment and is effective in controlling SWD. Timing is very important – spraying has to be done just as the cherries turn from yellow to pink or about 2-3 weeks before harvesting. In this window of time, adult flies can be killed before they are able to lay eggs in the fruit. A second application can be done in 7 to 10 days. Remember to carefully follow spraying directions and precautions as per the label.
Cultural Control – To reduce the worry of infestation of next year’s crop, be sure to clean up any fruit on the ground or left in trees. Seal it in a sturdy plastic bag and dispose of it in the garbage. Or solarize the fruit by placing it under clear plastic in the sun. This will effectively kill the flies.
The information given in the suggested UC website is much more detailed. Should you have further questions, we Master Gardeners will be happy to help find the answers. These management efforts take a bit of time and attention, but for me personally it has been well worth it!
Adult male spotted wing drosophila. (Photo by Martin Hauser)