- Author: Randall Oliver
Results help inform best practices for managing the disease-causing beetle
The University of California, Irvine campus is home to a vast urban forest consisting of approximately 30,000 trees located in a mix of landscape, riparian and open space settings. In the mid-2010s, that forest came under threat from an invasive species of beetle that arborists and pest researchers were just learning about – the polyphagous shothole borer.
The tiny beetles, which may have arrived in California from their native Southeast Asia via infested shipping materials, tunnel into trees and introduce a fungus that serves as food for adult beetles and their larva.
As the fungus grows, it colonizes the tree's vascular system, blocking transport of water and nutrients. This causes a disease called Fusarium dieback that can kill branches or entire trees.
One reason the beetles were such a threat at UCI was the high number of sycamores on campus, especially in Aldrich Park at the campus center. Hundreds of cottonwoods, native willows, golden rain and coral trees also were affected. In total, the beetles attacked more than 2,000 trees, including 75 different tree species.
A variety of approaches to controlling beetle
To better understand and tackle this problem, UCI's Facilities Management department and Office of Environmental Planning and Sustainability collaborated with researchers affiliated with UC Agriculture and Natural Resources and UC Cooperative Extension. In addition, pesticide-manufacturing companies, pest control advisers and arborists provided materials and labor to help offset the cost of research.
“UCI was the perfect testing ground to determine integrated pest management strategies for this beetle/disease complex,” said John Kabashima, UCCE environmental horticulture advisor emeritus. “Our research was multifaceted, delving into early detection, monitoring and sampling, and cultural and chemical management.”
Kabashima said UCI provided the researchers with “a lot of freedom” to try a variety of approaches and study the results over time.
“We could cut down and sample trees or leave selected infested trees alone; we explored a variety of pesticide/fungicide combinations and application techniques,” he said. “That freedom resulted in many of the management solutions that are used today to effectively control this pest.”
UCI and the researchers also established a full inventory of affected trees on campus, evaluating severity of infestation by the number of entry/exit holes and signs of dieback. One important key to management is getting rid of “amplifiers” – heavily infested trees that are both hazardous and a source of beetles to spread to other trees.
“Typically, shothole borer infestations begin with just a few trees that for some reason are highly attractive to the beetles – perhaps based on tree species, tree spacing, irrigation conditions or other factors,” Kabashima said. “Over time, the beetles and fungus multiply largely undetected in those few trees. When the beetle population reaches a critical point and the trees begin to die, the female beetles fly to adjacent trees in a secondary invasion, eventually infesting many trees over a large area.”
An opportunity to diversify UCI's urban forest
At UCI, that initial invasion took place in landscaped areas containing many large, majestic sycamores that were planted when the campus began operations in the mid-1960s.
Over several years, UCI removed 700 heavily infested trees, including many of those historic sycamores, and replaced them with other tree species.
Today, the forest at UCI is very different than it was in 2015. While shothole borers have not been eliminated completely, their presence is reduced significantly, and UCI now has the tools to manage them effectively. Reforestation efforts resulted in a diverse treescape that is not only more sustainable but also beautiful.
“Managing a 1,500-acre campus with 30,000 trees is a never-ending process,” said Richard Demerjian, UCI's assistant vice chancellor, Campus Physical & Environmental Planning. “Our forest continues to evolve, with an ongoing focus on increasing diversity and plant health.”
Demerjian also noted that UCI is now starting to consider planting new sycamore trees on a limited basis.
A primer on effective shothole borer management
Whether managing a forest of thousands of trees or just a few trees, landscape managers and residents can apply many of the lessons learned at UCI to control invasive shothole borers and other tree pests.
- Avoid monocultures. Tree diversity provides beauty and resiliency.
- Keep trees healthy. Proper irrigation and maintenance will keep trees strong and help protect them from shothole borers and other pests.
- Check trees. Look for the common signs and symptoms of infestation such as beetle entry/exit holes. Regular monitoring ensures that infestations are managed early, before they cause dieback or tree death.
- Confirm suspected infestations. Use the detection tool at www.ishb.org.
- Review management options. For trees with low infestation, prune the infested branches and monitor the tree's health over time. In non-riparian, urban settings, consider treating low and moderately infested trees with pesticides/fungicides demonstrated to be effective against the pest-disease complex (A licensed professional will be needed to apply the treatments). Severely infested trees may require removal.
- Call in a professional. A certified arborist or pest control professional would be able to provide recommendations based on the tree's condition. The local county Agricultural Commissioner's Office and UC Cooperative Extension office may have additional knowledge about current shothole borer monitoring and management programs in your area.
- Take care of green waste. The beetles can survive in cut wood for weeks or even months. Proper disposal of green waste includes chipping infested wood, followed by solarizing or composting the chips.
- Replant wisely. Begin planting new trees only after removing all amplifiers and establishing an ongoing monitoring program. Consider the current concentration of tree species when deciding what type of trees to plant.
- Author: Mike Hsu
Expanded from four chapters in the previous edition to 12, the third edition of Pesticide Safety: A Study Manual for Private Applicators aims to be more than just a study guide.
The manual, available for purchase in English and Spanish, provides much more detail on essential processes and procedures that will help keep applicators safe while using pesticides – as well as reduce environmental impacts from misapplication.
Published by University of California Agriculture and Natural Resources in collaboration with the state's Department of Pesticide Regulation, the manual – intended for members of the agricultural community who own, manage or work on farms that use restricted-use pesticides – also includes substantial updates.
The new manual reflects important changes to federal and state regulations since the publication of the previous edition in 2006.
“There are significant regulatory updates which help you stay up-to-date with safety rules and standards – and protect your workers from overexposure to pesticides,” said Lisa Blecker, technical editor of the publication, and currently a pesticide safety educator at Colorado State University.
In addition to emphasizing the broader ecological ramifications of improper pesticide use, the manual includes information on subjects that might get short shrift in other manuals, such as the correct calibration of equipment to ensure accuracy of application.
“All of that is now in the book and fully fleshed out,” Whithaus said. “[Applicators] are going to be able to do that much more effectively using the new book, compared to the old one – it was really hard to be thorough in 80-some pages.”
The new edition – totaling more than 200 substantive pages – also features a more streamlined and user-friendly layout modeled after a sister publication, The Safe and Effective Use of Pesticides, written for commercial applicators.
She highlighted the “knowledge expectations” listed at the beginning of each chapter and in the margins of the book, next to the relevant passages. The statements serve as “visual cues” to help readers learn and retain the material they need to pass California DPR's certification exam for private applicators.
And while the manual functions as an improved study aid for owners, managers and workers who apply pesticides, it doubles as a reference that they can turn to for years to come.
“It's going to be able to serve as a reference manual, as opposed to just a study guide,” Whithaus said. “You really will be able to use this book as a tool to help you do better in managing your land.”
The manual, listed at $29, is available for purchase in English at https://anrcatalog.ucanr.edu/Details.aspx?itemNo=3383 and in Spanish at https://anrcatalog.ucanr.edu/Details.aspx?itemNo=3394.
- Author: Alison Collin
At this time of year it pays to check any cherry trees for infestations of black aphids, Myzus cerasi. These appear most usually on the tips of the terminal shoots, but also on the spurs and they tend to prefer sweet cherry varieties over the sour ones. Leaves will crinkle and curl over, and become sticky with aphid secretions which in turn encourage the development of sooty mold that in severe cases may render the fruit inedible.
These aphids are shiny black and about 1/8-inch long. They overwinter as eggs on the tree bark and emerge at bud break when they feed on tender shoots, injecting a toxin into the leaves which causes them to curl thus protecting the aphids' increasing numbers.
UC IPM recommends using dormant oil sprays in late winter, and hosing off with jets of water any aphids that are obvious before the leaves curl. As with all aphid infestations keep an eye open for ants traveling up the tree trunk – a sure sign that they have found a good supply of honeydew. Natural predators such as hover flies, lady beetles, and lacewings should be encouraged, but once the leaves curl over, these insects appear not to be so prevalent. At that point water jets really are not effective, either.
On a young tree I have used a bucket of soapy water and bent the stems into it so that the affected regions are well submerged, but this is not possible on a large tree. Sometimes leaves are so infested that ones best option is to simply prune off the infected twigs, placing them directly into a plastic bag, and disposing of it.
Other cultural measures which may help are avoiding lush growth in the spring by not over-watering or using high nitrogen fertilizers. The base of the tree should be kept clear of weeds or other plants that may act as summer hosts.
- Editor: Tammy Majcherek
- Author: UC Integrated Pest Management Program
Report Unsolicited Seeds to APHIS
Have you had unexpected seeds show up in the mail? Unknown seeds could be invasive plants, contain invasive insects, or have plant disease causing agents. Here's what the United States Department of Agriculture Animal Plant and Health Inspection Service (USDA APHIS) has to say about it.
APHIS Stakeholder Announcement July 28, 2020 (Language from their website)
USDA Investigates Packages of Unsolicited Seeds
USDA is aware that people across the country have received suspicious, unsolicited packages of seed that appear to be coming from China. USDA's Animal and Plant Health Inspection Service (APHIS) is working closely with the Department of Homeland Security's Customs and Border Protection, other federal agencies, and State departments of agriculture to investigate the situation.
USDA urges anyone who receives an unsolicited package of seeds to immediately contact their State plant regulatory official or APHIS State plant health director. Please hold onto the seeds and packaging, including the mailing label, until someone from your State department of agriculture or APHIS contacts you with further instructions. Do not plant seeds from unknown origins.
At this time, [USDA does not] have any evidence indicating this is something other than a “brushing scam” where people receive unsolicited items from a seller who then posts false customer reviews to boost sales. USDA is currently collecting seed packages from recipients and will test their contents and determine if they contain anything that could be of concern to U.S. agriculture or the environment.
USDA is committed to preventing the unlawful entry of prohibited seeds and protecting U.S. agriculture from invasive pests and noxious weeds. Visit the APHIS' website to learn more about USDA's efforts to stop agricultural smuggling and promote trade compliance.
Questions?
Media Contact:
Cecilia Sequeira (301) 851-4054
K.cecilia.sequeira@usda.gov
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- Author: Siavash Taravati
Red imported fire ant (RIFA) control routine guidelines adopted by Los Angeles County school , protecting 500 school students from stings and contributing to improved community health and wellness.
The Issue
Red imported fire ant (RIFA, Solenopsis invicta, Fig. 1) is a venomous ant that was accidentally brought into California in 1989. Since its introduction, it has spread to many new territories in Southern California and Central Valley. RIFA infests lawns on parks, cemeteries, schools, houses, farms, etc. RIFA bites and stings people and its venom may cause anaphylactic shock in susceptible individuals. RIFA is currently found in many areas in Orange, Riverside, and San Bernardino counties. It is also becoming increasingly more problematic in the Merced County. In the Los Angeles County, it occurs near the borderline of Orange and San Bernardino counties. In 2017, the California School for the Deaf in Riverside experienced a severe RIFA infestation and school's ground crew had little success in trying to control RIFA on their 70-acres of land.
How UC Delivers
Dr. Siavash Taravati, an IPM advisor at UC Cooperative Extension office in the Los Angeles County was contacted by the California Department of Pesticide Regulation about this infestation. Taravati visited the school, spoke to the grounds crew on the field, inspected infested areas for RIFA mounds, collected some ant samples for identification, and took some pictures for the study. Later, Taravati created a new pest management program to help the school management reduce the level of RIFA infestations. This study was part of a RIFA management research program and was sponsored by the California department of pesticide regulation. Four different active ingredients were used for suppressing RIFA populations. Granular insecticides were distributed using a handheld spreader or manually by hand. Construction flags and marking spray paint were used to mark areas with RIFA activity. The school was visited by Taravati 2-3 times a month for insecticide applications and monitoring the infestation levels. The project duration was one year. RIFA activity was measured prior to and after treatment. RIFA population declined drastically shortly after the onset of UCCE's RIFA management efforts. After a few months, the number of RIFA mounds in many areas was decreased by 50 percent, and ultimately up to 95 percent in some of the athletic fields that used to be one of the most heavily infested spots. Similar results were obtained in other areas with 90 percent or more reduction in the number of mounds. Even when new mounds appeared periodically on the lawn, they were often small in size. Furthermore, unlike mature and large colony mounds, only a small number of ants emerged from these new mounds when they were poked with a rod.
The Impact
The RIFA control routine guidelines were adopted by the school staff upon finding the best practices from this research. They changed their primary pesticide management method from liquid insecticide applications to using granular baits as much as possible and talked to their supervisors and asked them for more support for their RIFA management efforts. As described above, this research shows that implementing this method decreases RIFA population, thus, protecting 500 school students from stings. Research shows these stings that can cause pain and discomfort and in some cases, life-threatening anaphylactic shock requiring immediate care. In this way, this applied pest management research and extension effort contributed to improved community health and wellness.
Testimonials
School ground crew: I really want to thank you for your great help. It was nice to have help with the fire ants. There aren't many places to get free help for fire ant control. Your work helped us to protect our school kids from being bitten during your reach for sure. We really liked your method of granular bait application and adopted it for better and more efficient fire ant control. Thanks
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