Posts Tagged: Mark Hoddle
Ag leaders, scientists set priorities to prevent invasive pest threats to the environment and economy
The gypsy moth, an interloper from Europe and Asia, is threatening California's majestic oaks in Ventura County.
Invasive desert knapweed, which comes from Africa, has made its first North American appearance in in California's Anza-Borrego Desert, where it has started to crowd out native plants.
Asian citrus psyllids are slowly spreading the devastating huanglongbing disease in Southern California citrus.
River rats from South America, called nutrias, are munching voraciously on wetland plants in some areas of Stanislaus, Merced and Fresno counties.
These are just a few of the insects, weeds, animals and diseases that have entered the state of California from elsewhere on the globe, causing tremendous ecological damage and huge economic losses to agricultural crops, which ultimately affect every resident of California.
Based on historical data, a new invertebrate species establishes itself in California about every six weeks, on average. They don't all become serious pest problems, but many evade eradication efforts, disrupt carefully balanced integrated pest management programs, hijack sensitive ecosystems, and spoil valued recreational resources and urban landscapes.
A diverse group of university scientists, federal and state government representatives, county agricultural commissioners and non-profit organization leaders who are battling these pests converged at a summit in the state capitol Jan. 11 and 12 to coordinate their efforts, pool intellectual resources, and plot a strategy for protecting agricultural crops, natural resources, unique ecological communities, cityscapes and residential neighborhoods.
“We are a big, beautiful, special place, blessed with great weather and diverse geography,” said California Department of Food and Agriculture Secretary Karen Ross at the summit. “That means a lot to our many visitors – including pests.”
“We know that collectively, we have the tools and expertise to prevent invasive species from entering California, spreading and becoming established,” Humiston said. “I am so pleased with the numbers of people here today, and the expertise that you bring.”
A fundamental component of the fight against damaging invasive species is research, Humiston said, adding that the European grapevine moth in an apt example. The pest was detected in California's wine country in 2009, and later found as far south as Fresno County. A multi-agency collaboration responded quickly.
UC ANR academics studied the moth's biology, life cycle, host range and proven management practices. They developed a pest management program that relied on mating disruption with pheromones and application of carefully timed insecticides. In short order, the moth population plummeted, and the state was declared free of European grapevine moth, lifting a quarantine, enhancing farmers' ability to export its product, and preserving the communities' economic wellbeing.
“This multi-agency collaboration contributed to a successful, science-based response plan to a serious pest threat,” Humiston said.
She noted, however, that prevention is the best option.
“This is critical,” Humiston said. “Once the pests are here, they cost us millions upon millions of dollars to manage, not to mention the devastation and destruction inflicted on our crops, natural resources and the damage to local economies.”
In 2010, CDFA created a strategic framework for addressing California's ongoing invasive pest problems and potential future introductions. Successful implementation of the framework requires partnerships involving government from the state to local levels, the agriculture industry and commodity groups, non-governmental organizations committed to the environment, and researchers at UC and other universities.
UC Cooperative Extension advisor emeritus John Kabashima was instrumental in bringing the summit to fruition. Kabashima, who retired in 2015, continues to lead a battle against invasive shot hole borer pests in Southern California. The insects, originally from Asia, are killing thousands of Southern California trees, and have the potential to kill millions of trees in urban areas, natural areas and even on farms in parts of the state as far north as Sacramento.
“We convened this meeting to bring together experts in the field and people who are feeling the impacts,” Kabashima said. “We're trying to start a 21st century invasive pest program that would then be implemented and funded to address the urgent issues before they cause any more devastation.”
At the end of the two-day summit, the participants voted to decide the most pressing issues and best strategies to take forward to their agencies, coalitions, research groups, legislators and constituents. Key strategies that emerged were:
- Analyze the economic impacts of invasive species management and the cost of “doing nothing.”
- Develop and maintain statewide surveys and map high-risk surveys.
- Increase funding to study invasive species' biology.
- Create a standing rapid response workgroup to guide response to new invasive species. Fund a rapid response emergency fund.
- Enact regulations to control high-risk vectors, such as soil, green waste, gravel, forage, straw and firewood.
- Formalize the Invasive Species Council of California (ISCC) and the California Invasive Species Advisory Committee (CISAC).
Mark Hoddle, UC Cooperative Extension biological control specialist and director of the Center for Invasive Species Research at UC Riverside, said the summit was a valuable part of the ongoing battle against invasive pests.
“It's good to see the number of agencies and organizations involved with invasive species issues,” Hoddle said. “I'm impressed with the energy in coming up with these priority lists.”
Summit outcomes will include sending recommended action items to the Legislature for funding consideration.
“Without financial support, many of the management tools that prevent unwanted incursions, find and monitor incipient pest populations, and develop sustainable, cost-effective management programs won't be possible,” Hoddle said.
View Glenda Humiston's opening remarks here:
Representatives from the date and ornamental palm industries, arborists and pest managers, parks and recreation officials, and home owners are uniting behind a University of California, Riverside initiative to slow the spread of the South American palm weevil, a palm tree-killing insect that has established in San Diego County.
“Everyone recognizes the threat and agrees it is significant,” said Mark Hoddle, UC Cooperative Extension specialist in biological control based at UC Riverside.
However, Hoddle said, action is hampered significantly by a lack of financial support at the state and federal level for research to answer questions about the distribution of the weevil in Southern California, how far it can fly from infestation zones, control options, and the most efficient and sensitive ways to monitor and trap it.
Hoddle recently helped organize a symposium just outside San Diego on the South American palm weevil. Recent detection in California of the weevil, which has traditionally been found in South and Central America, the Caribbean and Mexico, has scientists, farmers and nursery industry officials worried because it threatens California's $70 million ornamental palm industry and $68 million commercial date industry.
“My personal feeling is we might be on the verge of a crisis now,” Hoddle said. “The big problem is we don't know how far the weevil has spread. We really need help from the public in tracking its spread.”
The South American palm weevil (Rhynchophorus palmarum) is not to be confused with the palm weevil Rhynchophorus vulneratus, which originated from Indonesia and was incorrectly identified as the red palm weevil, Rhynchophorus ferrugineus, when it was found killing palm trees in Laguna Beach in 2010. R. vulneratus was declared eradicated from California on Jan. 20, 2015.
Feeding by larvae of the South American palm weevil damage the growing area of the crown of palm trees. The tree is then unable to produce new fronds, and within months it dies. Canary Islands date palms are particularly vulnerable and it is likely date palms will be attacked too. California also has a native palm species (Washingtonia filifera), which grows in desert oases and may be vulnerable to attack.
Detection of the South American palm weevil was officially confirmed May 9, 2011. Seven additional detections were made in July and August 2011. These initial detections by the USDA were in San Ysidro in San Diego County, about two miles from the Mexican border. It is likely that the weevils flew from Tijuana, Mexico, where infestations and dead palms had been detected in December 2010.
As a result of those detections, weevil traps were set up throughout California, Arizona and Texas with financial support from the USDA. A total of 111 South American palm weevils were captured in California; 109 in San Diego County and two in Imperial County. They were also found in Alamo, Texas, and Yuma, Ariz.
The traps were monitored from 2011 to 2013. Then, monitoring stopped when federal funding for the program expired.
Since monitoring stopped, it appears the problem has worsened, said Hoddle, who is also director of UC Riverside's Center for Invasive Species Research. In May 2016 he did a casual eight-hour driving survey in Tijuana, Mexico and found about 125 dead Canary Islands date palms that had been killed by the South American palm weevil.
In August, 2016, Hoddle placed 10 weevil traps at Sweetwater Regional County Park, about 15 miles east of San Diego. Since then, he has been catching about five to seven weevils per trap per month. In the coming months, he plans to start monitoring the heath of the palm trees in Sweetwater Regional Park using a drone.
Hoddle considers the South American palm weevil situation more dire than what he encountered with Rhynchophorus vulneratus because he fears the South American palm weevil has spread further and it spreads the red ring nematode (Bursaphelenchus cocophilus), which also kills palm trees.
Red ring nematodes, which have not yet been detected in California, can enter palm trees through the damage South American palm weevils do to the trees. The nematodes can also enter the bodies of the weevils when they are larvae. Then, the larvae turn into adult weevils which are strong flyers and they can then spread the nematode to other palms when the feed or lay eggs on them.
on many fronts, motivated by the insect's ability to spread huanglongbing (HLB), the worst citrus disease in the world. HLB has been found in only one isolated tree in California, and everybody who enjoys California citrus wants it to stay that way.
Farmers are diligently treating orchards where the pest has been found, county ag commissioners are monitoring traps to keep tabs on ACP movement, and UC researchers are looking into a wide variety of novel techniques to disarm ACP and the disease. In December, UC Cooperative Extension biological control specialist Mark Hoddle began releasing a newly imported natural enemy of ACP, Diaphorencyrtus aligarhensis (DA).
“We've released about 2,000 now at select urban sites,” Hoddle said. “It's too early to tell if we are getting attacks, but we are monitoring carefully for this type of activity.”
Hoddle said it isn't the ideal time for DA to become established in California citrus. Cool weather and short days have hindered ACP population growth, so DA likely are struggling to find enough ACP to attack.
“But we keep pumping them out there as the alternative is letting them to die in quarantine,” Hoddle said. “At least if they are outside they may find some ACP to kill.”
UC Division of Agriculture and Natural Resources in 1997. He collected DA in Pakistan three years ago, then raised and studied colonies of the sesame-seed-sized insect in quarantine at UC Riverside. The wasp joins a cousin, Tamarixia radiata, also imported from Pakistan by Hoddle, to search out and destroy Asian citrus psyllid. He began releasing Tamarixia in 2011.
Since then, CDFA has raised a million Tamarixia and released them in Southern California for ACP management. It appears Tamarixia has become established, is moving around on its own and killing Asian citrus psyllids. State and federal agencies are now beginning to work with DA as well.
“We've given starter colonies of the new insect to CDFA. They have a mass rearing facility at Mt. Rubidoux in Riverside, where they currently mass produce Tamarixia,” Hoddle said.
USDA plans to set up field cages around citrus trees in late spring or early summer and prune them severely to encourage new growth. ACP will be placed in the cages to enjoy the fresh, aromatic stems and leaves on the trees, and DA will be released in large numbers to attack the ACP.
“Infested branches will be trimmed off trees, taken to the lab where parasitoids are then harvested,” Hoddle said. “The adult ACP will be trapped inside the cages and killed.”
For more details, photos and a video about the new enemy of Asian citrus psyllid, see the Center for Invasive Species Research website.
An initiative to manage endemic and invasive pests and diseases is part of UC Agriculture and Natural Resources Strategic Vision 2025.