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Invasive species threaten California’s economy and ecology

Invasive species threaten California's landscapes.
When insects, weeds, animals and diseases enter California from elsewhere in the nation or world, they can cause economic losses to agricultural crops and ecological damage to the state's natural areas. Ultimately, invasive species 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.

UC Agriculture and Natural Resources joins the California Department of Fish and Wildlife and the California Invasive Species Council in marking California Invasive Species Action Week, June 1-9, to raise public awareness of invasive species issues and promote public participation in the fight against California invasive species.

The UC Integrated Pest Management Program and the Center for Invasive Species Research are two UC ANR programs that monitor invasive species and coordinate responses when they become established in the state. They work closely with UC ANR advisors and specialists on eradication, management and prevention of these threats.

Asian citrus psyllid and huanglongbing

Huanglongbing disease, which kills citrus trees, is spreading in Southern California residential areas and threatening commercial citrus production. There is currently no cure for the huanglongbing disease. It is spread by the Asian citrus psyllid. The insect, a native of Pakistan, Afghanistan and other Asian regions, was first detected in California in 2008. Currently the only way to control the disease is to reduce the psyllid population and to remove trees that are infected or located near the infected trees. Everywhere ACP is found, the pests find and spread HLB. In California, an aggressive push to keep psyllid populations low, regulations to limit the spread of psyllids when trucking the fruit, and active scouting for and removal of HLB-infected trees in residential areas could buy time for researchers to find a solution before California suffers the fate of Florida citrus growers, whose orange production has dropped 70% lower than 20 years ago. More info: ACP/HLB distribution and management

Brown marmorated stink bug

The first reproducing population of brown marmorated stink bug was found in Los Angeles County in 2006. In 2013, a large population was detected in a midtown Sacramento. A pest of agricultural crops and a serious residential problem, it is a strong flier and also travels long distances by hitching rides in vehicles or inside furniture or other articles when they are moved, often in late summer and early fall. As a result, new infestations pop up in neighborhoods where people travel from infested areas. A native of China, Japan and Korea, BMSB was first documented in the United States in Pennsylvania in 2001. It is either established or found occasionally in about 41 states. More info: Pests in Gardens and Landscapes - Brown marmorated stink bug

South American palm weevil

The South American palm weevil is a destructive pest in its native and invaded ranges. Scientists first found it in San Diego in 2011. As the weevils feed, they drill through the heart of the palm, eventually choking off the fronds and killing the tree. UC ANR is studying the South American palm weevil's biology and life cycle, and trying to find out how they got to California. Traps for monitoring the pest have been developed and deployed. More info: South American palm weevil invasion in San Diego County




Polyphagus shot hole borer

The insect, originally from Asia, was first identified in California in 2012. Shot hole borers bore through bark carrying with them harmful fungus. The fungus attacks the tree's vascular tissue, choking off water, causing branch dieback and eventually killing the tree. Polyphagous shot hole borer and the fungus are now distributed widely in more than 110 types of trees in Los Angeles and Orange counties, and have been observed in San Bernardino, Riverside and San Diego counties. More info: Invasive shot hole borers

Sudden oak death

Sudden oak death is caused by the pathogen Phytophthora ramorum, which was inadvertently introduced to California forests on nursery stock in the 1990s. The disease has killed up to 50 million trees (primarily tanoak, coast live oak, California black oak, Shreve's oak and canyon live oak) from Big Sur to southwest Oregon. More info: http://www.suddenoakdeath.org

Dyer's woad

Dyer's woad is an invasive weed thought to have been introduced into California in the Scott Valley of Siskiyou County, where it is locally referred to as "Marlahan mustard." Until a couple of decades ago, it was primarily confined to Scott Valley, but it has subsequently spilled over into Shasta Valley. It continues to spread throughout Siskiyou County and into Modoc, Shasta and other northern California counties. During medieval times, Dyer's woad was one of the most valuable plant commodities in Europe, cultivated as a source of blue dye as early as the 13th century. Colonists first introduced it to the eastern United States for that purpose. UC ANR researchers are developing management practices for removing Dyer's woad and using solarization to kill the seeds in the field, limiting the risk of seed being spread when dead weeds are removed for disposal. More info: UC IPM Pest Note on Dyer's Woad

Yellow starthistle

Yellow starthistle is native to Eurasia and was introduced to California around 1850 via South America. Recent reports indicate that yellow starthistle infests between 10 and 15 million acres in California. It is common in open areas on roadsides, rangeland, wildlands, hay fields and pastures. Disturbances created by cultivation, poorly timed mowing, road building and maintenance, or overgrazing favor this rapid colonizer. It forms dense infestations and rapidly depletes soil moisture, preventing the establishment of other species. It is also poisonous to horses, causing a nervous disorder called “chewing disease,” which is fatal once symptoms develop. Horses are the only animal known to be affected in this manner and should not be allowed to graze on yellow starthistle. More info: UC IPM Pest Note on yellow starthistle

Saltcedar

Saltcedar is native to Eurasia and was introduced into California through the nursery industry. The weed is tolerant of high salinity. Saltcedar's dry branches and leaves can increase fire frequency. After fires, saltcedar sprouts rigorously, while native trees and shrubs generally do not, enabling saltcedar groves to push out native species. Research shows that saltcedar could impact the structure and dynamics of streams by trapping and stabilizing sediments, increasing overbank flooding following high flow events and creating permanent sand bars in rivers. This pest also contributes to the decline of wetland communities as habitat refuge for wildlife. More info: Center for Invasive Species Research

Arundo donax

Arundo donax is native to the Mediterranean and tropical Asia. In California from the late 1700s to early 1800s, giant reed was often planted for erosion control in flood channels and as wind breaks. The bamboo-like perennial can grow to 25 feet tall with thick, well-developed rhizomes. It develops dense stands that displace native vegetation, diminish wildlife habitat, increase flooding and siltation in natural areas and create a wildfire hazard. More info: Arundo donax

Egyptian broomrape

Egyptian broomrape was found in a California processing tomato field in 2015 – a first find for the U.S. It is a parasitic plant that attaches to other plant roots and lacks conspicuous leaves. Broomrape can infest about 30 broadleaf crops, including bell pepper, cabbage, carrot, celery, eggplant, melons, potato and tomato. The presence of broomrape in a field may force farmers to plant a less economical, non-host crop or to leave the field fallow. The weed causes reductions in crop yield, adversely impacts crop quality and results in the loss of cultivated land due to reduced crop alternatives. More info: Egyptian broomrape.

Japanese dodder

There are several species of dodder native to California, but they are not as difficult to manage as Japanese dodder, which was identified in Shasta and Yuba counties in 2005. This invasive plant pest has thick stems that resemble spaghetti. It grows larger and faster than native dodders and can cover entire trees or shrubs. In California, no viable seeds have been observed following Japanese dodder flowering. Instead, most spread occurs through the dissemination of small pieces of stems distributed by birds and other animals or through pruning, composting, and the improper disposal of infested plant material. This weed is has spread to more than a dozen California counties including Alameda, Butte, Contra Costa, Fresno, Los Angeles, Merced, Sacramento, Shasta, Solano, Sutter, Tulare, Yolo, and Yuba. Contact your county agricultural commissioner to receive proper identification and help with control. More info: UC IPM

 

 

Find more information on the UC Integrated Pest Management Program Invasive and Exotic Pests website: https://www2.ipm.ucanr.edu/Invasive-and-Exotic-Pests/

 

 

Posted on Friday, May 31, 2019 at 2:22 PM
Tags: invasive species (19)
Focus Area Tags: Pest Management

A team approach is key to conquering invasive species

UC ANR teams with other universities, government agencies, non-profit organizations, landowners and California residents in the fight to prevent, eradicate or control invasive species.
The UC Integrated Pest Management Program and the Center for Invasive Species Research are two UC Agriculture and Natural Resources programs that monitor invasive species and coordinate responses when they become established in the state. They work closely with UC ANR advisors and specialists, government agencies and nonprofit organizations on eradication, management and prevention of these threats.

At an invasive species summit last year in Sacramento, UC ANR vice president Glenda Humiston and California Department of Food and Agriculture secretary Karen Ross convened scientists, government representatives and volunteers to pool intellectual resources and plot a strategy for protecting agricultural crops, natural resources, cityscapes and residential neighborhoods from invasive species.

“We know that collectively, we have the tools and expertise to prevent invasive species from entering California, spreading and becoming established,” Humiston said.

Below are three examples of pests that entered California, and with research, collaboration and treatment, were eradicated from the state.

European grapevine moth

European grapevine moth, a native of Mediterranean Europe, was detected for the first time in the Americas in Chile in April 2008. The following year, European grapevine moth was found in California's iconic wine region, Napa Valley. From there it spread to nine other California counties, as far south as Fresno. UC ANR academics responded rapidly — working with public and private partners and international scientists — to develop a pest management program that relied on deploying pheromone dispensers to disrupt mating and application of carefully timed insecticides. UC ANR academics studied the moth's biology, life cycle, host range and proven management practices. In short order, the moth population plummeted, and eventually the state was declared free of European grapevine moth, lifting a quarantine, enhancing farmers' ability to export their agricultural products, and preserving the communities' economic wellbeing. More info: Growers, scientists and regulators collaborate on European grapevine moth program

 


European grapevine moth
 

Pink bollworm of cotton

It took 50 years, but the invasive pink bollworm of cotton was declared eradicated in California in 2018. Eradication of pink bollworm was a joint effort by UC Cooperative Extension, USDA's Agricultural Research Service, county agricultural commissioners' offices and California cotton growers. It involved the implementation of integrated pest management techniques, such as planting transgenic cotton, using insect pheromones to disrupt mating, releasing sterile insects to slow reproduction, plowing after each crop to provide host-free periods, and extensive surveying. California cotton growers funded the program by paying an assessment on cotton grown in the state. More info: Pink bollworm UC Pest Management Guidelines
 
Pink bollworm larvae

Red palm weevil

In August 2010, arborists removed a dying Canary Island date palm from the yard of a Laguna Beach home and reported finding large black and red striped beetles. The pests were confirmed to be the first record of the destructive red palm weevil in the U.S. Hormone monitoring and visual surveys of other palms in the area confirmed the presence of the pest. Rapid action was taken against the pest by applying pesticides to trees that showed feeding damage to palm fronds. Effective surveying was accomplished by combining hormone attractants and cut pieces of palm trees provided by the California date palm industry. The last live weevil was detected in Laguna in January 2012. After three years passed with no weevil detections in Laguna Beach, USDA-APHIS declared this pest to be officially eradicated in January 2015. More info: Red palm weevil successfully eradicated form California
 
Red palm weevil

 

 

 

 

 

Posted on Friday, May 31, 2019 at 2:22 PM
Tags: invasive species (19)
Focus Area Tags: Pest Management

During California Invasive Species Action Week, learn about invasive species

Californians can help in the fight against invasive species by learning and participating during California Invasive Species Action Week, June 2–10.

During the week, the UC Statewide Integrated Pest Management Program invites the public to spend lunch learning about invasive tree killing pests, aquatic nasties like quagga mussels and nutria, and how the invasive weed/wildfire cycle is altering our ecosystems. http://ucanr.edu/sites/invasivelunch/

The invasive species killing trees is causing sugar volcanoes to erupt on avocado trunks and branches that might be infected with Fusarium dieback. Fusarium dieback is a invasive, beetle-vectored disease that causes damage on avocado and more than 39 other tree species. The disease has spread in urban forests and wild lands in the Los Angeles basin since early 2012, and in Orange and San Diego counties since early 2013 and Ventura County in 2015.

The symptoms — staining, sugary exudate, gumming and beetle frass — are often noticed before the tiny beetles (1.5–2.5 mm) are found.

As its name suggests, these beetles bore into trees. Near or beneath the symptoms, you might notice the beetle's entry and exit holes into the tree. The female tunnels into trees forming galleries, where she lays her eggs. Once grown, the sibling beetles mate with each other so that females leaving the tree to start their own galleries are already pregnant. Males do not fly and stay in the host tree.

Shothole borers have a special structure in their mouth where they carry two or three kinds of their own novel symbiotic fungi. Shothole borers grow these fungi in their tree galleries. It's these fungi that cause Fusarium dieback disease, which interrupts the transportation of water and nutrients in the host tree. Advanced fungal infections will eventually lead to branch dieback.

Early detection of infestations and removal of the infested branches will help reduce beetle numbers and therefore, also reduce the spread of the fungus.

  • Chip infested wood onsite to one inch in size or smaller. If the branch is too large to chip, solarize them under a clear tarp for several months
  • Avoid movement of infested firewood and chipping material out of infested area

Avocado is one tree host. Shothole borers successfully lay eggs and grow fungi in many tree hosts, with some of these trees susceptible to the Fusarium dieback disease. For more information about tree host species, where the shothole borer is in California, and what symptoms look like in other tree hosts, visit the UC Riverside Eskalen Lab website or the Invasive Shot Hole Borers website.

Content in this post taken from the UC IPM Avocado Pest Management Guidelines. Faber BA, Willen CA, Eskalen A, Morse JG, Hanson B, Hoddle MS. Revised continuously. UC IPM Pest Management Guidelines Avocado. UC ANR Publication 3436. Oakland, CA.

Posted on Monday, June 4, 2018 at 1:04 PM
Focus Area Tags: Agriculture

Invasive pest takes up residence in the Northeast

Spotted lanternfly. (Photo: Wikimedia Commons)
The spotted lanternfly, native to Asia, first came to America in 2014 when it was found in Pennsylvania. Despite a quarantine, populations have been discovered in New York, Delaware and Virginia, reported Zach Montague in the New York Times.

“They've been appearing in grapes, and we have reports from growers last year of a 90 percent loss,” said Julie Urban, a senior research associate at Penn State.

The reporter also contacted UC Cooperative Extension advisor Surendra Dara, who published an article in 2014 about spotted lanternfly in Pest News, a UC Agriculture and Natural Resources eJournal about endemic and invasive pests in California.

Surendra Dara.
"The Pennsylvania Department of Agriculture recently reported the first detection of yet another invasive hemipteran pest in the U.S.," Dara wrote in his article. "While efforts to have a good grip over other invasive hemipterans like the Asian citrus psyllid, the Bagrada bug, and the brown marmorated stink bug are still underway, there is a new pest that could potentially impact industries ranging from lumber to wine."

Dara told Times' reporter that lanternfly has the unusual ability to lay eggs on almost any surface — plants and soil as well as wheel wells, train cars and shipping containers.

“Most pests deposit their eggs on their host plant, or very close, so they already have food available,” Dara said. “Those that have the advantage of being able to lay eggs on non-plant material obviously have a better chance of surviving and spreading."

Posted on Monday, May 21, 2018 at 1:21 PM
Focus Area Tags: Agriculture

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.”

Glenda Humiston, vice president of UC Agriculture and Natural Resources, said research is a fundamental component of the fight against damaging invasive species.

Glenda Humiston, vice president of UC Agriculture and Natural Resources, which co-sponsored the summit, outlined the goals.

“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 led a break out session on arthropods during the summit.

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.”

Summit participants prepare to vote on most pressing invasive species' issues and best management strategies.

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: 

Posted on Thursday, January 18, 2018 at 8:21 AM

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