Division of Agriculture and Natural Resources
Division of Agriculture and Natural Resources
Division of Agriculture and Natural Resources
University of California
Division of Agriculture and Natural Resources

Posts Tagged: Mark Hoddle

Palm weevil threatens So Cal palm trees

Dead palms located at Glenn Abbey in San Diego County. Photo by Mark Hoddle

More than 20,000 palms in the region have been killed by South American palm weevil

The swaying palm trees that line San Diego's streets might not be swaying much longer due to a pest that is infecting many of these iconic trees and making its way across Southern California. 

The South American palm weevil (SAPW), also referred to as the American palm weevil and black palm weevil, was first detected in San Diego County in 2011, with breeding populations found in a Canary Island date palm in San Ysidro in 2015. According to industry experts, more than 20,000 palms in the region have been killed by SAPW thus far.

While SAPW can attack a variety of palm tree species, Canary Island date palms (Phoenix canariensis) are by far their most preferred host. SAPW adults lay their eggs in the crown of palm trees and then larvae hatch and voraciously consume the growing tissue of the palm. If left unchecked, this pest can kill mature palms in a matter of months.

SAPW has affected neighborhoods and cities throughout the greater San Diego area, creating a need for more residents to be aware of this concern and report infected palms. Though infestation has not been confirmed, SAPW adults have been reported in the Coachella Valley – about 120 miles northeast of San Diego.

‘Super-dispersers' from San Diego can fly long distances

A South American palm weevil can fly for as long as five hours. “They are on a death mission when they fly long distances – find food or die trying!" says Mark Hoddle, UC Cooperative Extension entomology specialist. Photo courtesy of Mark Hoddle

The California Department of Food and Agriculture has trapped weevils in the Coachella Valley and recent posts on iNaturalist, a social network for community members to map and share observations of biodiversity across the globe, indicate that adult weevils are flying into areas where edible dates are grown. 

These reports interest researchers like Mark Hoddle, University of California Cooperative Extension based at UC Riverside, because the Coachella Valley, the major production area for edible dates nationwide, is far from any known infested palm trees.

How did the weevils get there? “It may be super-dispersers from San Diego,” said Hoddle. “They are on a death mission when they fly long distances – find food or die trying!”

While conducting an experiment to assess SAPW's flight capability, Hoddle and his team learned that the beetle could fly non-stop for up to five hours, with some variation between males and females. “In some cases, they will fly until they die,” Hoddle said.

Currently, Hoddle is managing an ongoing urban palm surveillance effort of 521 palm trees in and around Bonita in San Diego County, which are assessed every six months. More than 70% of these palms have been killed by SAPW over a 6.5-year period.

Although Canary Island date palms are highly preferred by SAPW, the weevils can complete their entire life cycle in sugarcane as well. For palm species that are not currently preferred by the pest, there is still a chance that they can become more preferred over time as SAPW works its way through all available Canary Island date palms in the region.

Traps can be used to monitor for weevils and reduce the number of weevils flying around, say Hoddle, left, and Eric Middleton, UCCE integrated pest management advisor. Photo by Robert Padilla

Taking action to protect your palms 

There are steps that one can take to protect palm trees. Traps can be used to both monitor weevils and reduce the number of adults flying around. There are two types of traps that Hoddle has evaluated for weevil captures: the bucket trap and the Picusan trap. Both use a fermenting bait – prepared with dates, baker's yeast and water – that is placed in a glass jar with a perforated lid, in addition to a commercially available aggregation pheromone that will attract male and female weevils. 

Of the two trap types, Hoddle prefers Picusan traps because they catch about six times as many weevils as bucket traps – retaining more than 95% of the weevils that are attracted to them. Bucket traps, on the other hand, retain only about 30% of weevils.

Hoddle emphasizes that trap placement is key. The Picusan trap is designed to be placed on the ground, whereas the bucket trap is typically hung from a tree branch, fence or post. Furthermore, the traps should be placed at least 500 yards away from the potential host palms and avoid direct sunlight. Shaded or partially shaded areas are best to avoid diminishing the trap's potency.  

Another strategy is to prune palm trees when SAPW flight activity is low (December through March) to minimize attracting flying adult weevils to freshly pruned palms.

Finally, the best way to protect your tree is to apply insecticides. These chemicals will kill adult weevils that attempt to start infestations. While contact insecticides can deter and kill adults when applied to the crown of the palm, systemic insecticides are usually more effective and can be applied as soil and crown drenches, trunk sprays, or soil and trunk injections. Systemic insecticides move inside the palm and concentrate in the palm heart, the growing area at the top of the palm where weevils feed. Once this growing area is damaged by feeding weevil larvae, palms die.

“Just know that if you are planning to protect palms with insecticides, you are in it for life,” saidHoddle, emphasizing that there is no “one and done” approach to saving palms affected bySAPW. “Don't start if you can't commit. 

Mark Hoddle, standing on left, and Eric Middleton, standing on right, lead a group of workshop participants on a tour of Sweetwater Summit Regional Park to examine dead or infected palms. Photo by Robert Padilla

Aesthetics aren't the only motivation to prevent palm infection and death caused by SAPW. Palm crowns that are highly damaged by larval feeding can detach from the top of the trunk and fall to the ground, putting people and property at risk. Dead fronds drop from dying palms and the large spines at the base of the fronds are a significant hazard to people and pets.

Seek expert support for tree concerns and removal

Removing dead palms is an expensive and time-consuming process. Removal can cost between $2,400 to $4,000 per palm, with cost varying based on location. For example, if a palm is in an area that requires the use of a crane, semitruck or helicopter to safely access, remove and dispose of the dead palm, tree removal can cost up to $15,000.

Once a palm is infested with SAPW, it likely cannot be saved unless it is aggressively treated with insecticides at an early stage of the infestation. If you are certain that a tree is infected by SAPW, it is highly recommended that you work with a tree care company or arborist to manage the weevils that might be present in the palm and to promptly and responsibly dispose of dead palms so that spread of weevils into new areas is minimized.

To confirm visual signs of palm trees that have been affected by SAPW, visit Hoddle's site for more information and to report infested palms: https://cisr.ucr.edu/invasive-species/palmarum-survey.

To read this story in Spanish, visit: https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=58381

Posted on Monday, November 6, 2023 at 9:11 AM
  • Author: Saoimanu Sope
Focus Area Tags: Environment

Climate-Change Resources

University of California UC ANR Green Blog (Climate Change and Other Topics) https://ucanr.edu/blogs/Green/index.cfm?tagname=climate%20change (full index)

Examples:

     -  Save Trees First: Tips to Keep Them Alive Under Drought https://ucanr.edu/b/~CdD 

     - Landscaping with Fire Exposure in Mind: https://ucanr.edu/b/~G4D

     - Cities in California Inland Areas Must Make Street Tree Changes to adapt to Future Climate  https://ucanr.edu/b/~oF7

 
 

Drought, Climate Change and California Water Management Ted Grantham, UC Cooperative Extension specialist (23 minutes) https://youtu.be/dlimj75Wn9Q

Climate Variability and Change: Trends and Impacts on CA Agriculture Tapan Pathak, UC Cooperative Extension specialist (24 minutes) https://youtu.be/bIHI0yqqQJc

California Institute for Water Resources (links to blogs, talks, podcasts, water experts, etc.) https://ciwr.ucanr.edu/California_Drought_Expertise/

UC ANR Wildfire Resources (publications, videos, etc.) https://ucanr.edu/News/For_the_media/Press_kits/Wildfire/ (main website)

      -UC ANR Fire Resources and Information https://ucanr.edu/sites/fire/ (main website)

            -Preparing Home Landscaping https://ucanr.edu/sites/fire/Prepare/Landscaping/

UC ANR Free Publications https://anrcatalog.ucanr.edu/ (main website)

- Benefits of Plants to Humans and Urban Ecosystems: https://anrcatalog.ucanr.edu/pdf/8726.pdf

 -Keeping Plants Alive Under Drought and Water Restrictions (English version) https://anrcatalog.ucanr.edu/pdf/8553.pdf

  (Spanish version) https://anrcatalog.ucanr.edu/pdf/8628.pdf

-  Use of Graywater in Urban Landscapes https://anrcatalog.ucanr.edu/pdf/8536.pdf

-  Sustainable Landscaping in California https://anrcatalog.ucanr.edu/pdf/8504.pdf

 

Other (Non-UC) Climate Change Resources

Urban Forests and Climate Change. Urban forests play an important role in climate change mitigation and adaptation. Active stewardship of a community's forestry assets can strengthen local resilience to climate change while creating more sustainable and desirable places to live. https://www.fs.usda.gov/ccrc/topics/urban-forests

Examining the Viability of Planting Trees to Mitigate Climate Change (plausible at the forest level) https://climate.nasa.gov/news/2927/examining-the-viability-of-planting-trees-to-help-mitigate-climate-change/

Reports and other information resources coordinated under the auspices of the United Nations and produced through the collaboration of thousands of international scientists to provide a clear and up to date view of the current state of scientific knowledge relevant to climate change. United Nations Climate Action

Scientific reports, programs, action movements and events related to climate change. National Center for Atmospheric Research (National Science Foundation)

Find useful reports, program information and other documents resulting from federally funded research and development into the behavior of the atmosphere and related physical, biological and social systems. Search and find climate data from prehistory through to an hour ago in the world's largest climate data archive. (Formerly the "Climatic Data Center") National Centers for Environmental Information (NOAA)

Think tank providing information, analysis, policy and solution development for addressing climate change and energy issues (formerly known as the: "Pew Center on Global Climate Change"). Center for Climate & Energy Solutions (C2ES)

Mapping Resilience: A Blueprint for Thriving in the Face of Climate Disaster. The Climate Adaptation Knowledge Exchange (CAKE) was launched in July 2010 and is managed by EcoAdapt, a non-profit with a singular mission: to create a robust future in the face of climate change by bringing together diverse players to reshape planning and management in response to rapid climate change. https://www.cakex.org/documents/mapping-resilience-blueprint-thriving-face-climate-disaster

Cal-Adapt provides a way to explore peer-reviewed data that portrays how climate change might affect California at the state and local level. We make this data available through downloads, visualizations, and the Cal-Adapt API for your research, outreach, and adaptation planning needs. Cal-Adapt is a collaboration between state agency funding programs, university and private sector researchers https://cal-adapt.org/

Find reports, maps, data and other resources produced through a confederation of the research arms of 13 Federal departments and agencies that carry out research and develop and maintain capabilities that support the Nation's response to global change. Global Change (U.S. Global Change Research Program)

The Pacific Institute is a global water think tank that combines science-based thought leadership with active outreach to influence local, national, and international efforts to develop sustainable water policies. https://pacinst.org/our-approach/

Making equity real in climate adaptation and community resilience policies and programs: a guidebook. https://greenlining.org/publications/2019/making-equity-real-in-climate-adaption-and-community-resilience-policies-and-programs-a-guidebook/ 

Quarterly CA Climate Updates and CA Drought Monitor Maps (updated each Thursday) https://www.drought.gov/documents/quarterly-climate-impacts-and-outlook-western-region-june-2022

 

 

 

 

Posted on Wednesday, May 10, 2023 at 1:21 PM
Focus Area Tags: Environment

Drought focus of Water Resources IMPACT magazine special issue

Michael Yang, left, discusses a new irrigation with a Hmong farmer. Photo by Ruth Dahlquist-Willard

UC ANR experts address emotional toll of drought

Preparing the American West for prolonged drought is the focus of a double issue of Water Resources IMPACT magazine. The California Water Commission staff are guest editors for this special open-access edition of the magazine, which is published by the American Water Resources Association.   

Faith Kearns, academic coordinator of University of California Agriculture and Natural Resources' California Institute for Water Resources, is among the authors delving into how drought impacts people and the environment and how we can better prepare for the inevitable. 

The first issue, published on Feb. 14, focuses on water scarcity issues confronting California and the ways these issues affect different sectors. 

In “Trauma, Care, and Solidarity: Addressing the Emotional Toll of Chronic Drought,” Kearns highlights the effects of drought on mental health. She points to the spike in suicide hotline calls when wells ran dry in Southeast Asian communities in California's Central Valley.

By listening to Southeast Asian farmers, Ruth Dahlquist-Willard and Michael Yang of UC Cooperative Extension were able to “lighten the load” for them by providing pragmatic support, Kearns writes.

“The scale of some of these highly emotional issues – drought, wildfires, climate change – can make them seem incredibly difficult, if not impossible, to deal with,” Kearns said. “At the same time, they are affecting everyone living in the western U.S. on a daily basis. I wanted to highlight and provide models based on work that people – whether they are researchers, clinical psychologists, or Cooperative Extension advisors – are doing right now to ease the way.”

The authors who contributed to the double issue are a diverse array of Tribal experts, academics, nongovernmental organization thought-leaders, water managers and water policy influencers, each of whom brings their own perspective on the topic of drought. Their expertise and perspectives in climate science, water policy and water management will help inform drought-related decision-making and support policies that better prepare the state to thrive during periods of prolonged water scarcity.

Not all effects of drought are as easy to see as on this parched hillside. Photo by Faith Kearns

In addition to Kearns, the first issue includes articles contributed by:

  • Samantha Stevenson, University of California, Santa Barbara
  • Jay Lund, University of California, Davis
  • Ron Goode, North Fork Mono Tribe
  • Andy Fecko, Placer County Water Agency
  • Jeff Mount, Public Policy Institute of California, and Ted Grantham, University of California, Berkeley/UC Cooperative Extension
  • Nat Seavy and Karyn Stockdale, National Audubon Society
  • Kjia Rivers, Community Water Center
  • Cannon Michael, Bowles Farming
  • Michelle Reimers, Turlock Irrigation District

The January/February edition of Water Resources IMPACT magazine can be accessed, free of charge, on the American Water Resources Association website at https://www.awra.org under “Publications.”

The second issue, to be published in March, will focus on drought response, considering the options for adaptation. This two-part series complements the Commission's work on strategies to protect communities and fish and wildlife in the event of a long-term drought.

 

 

Posted on Thursday, February 16, 2023 at 10:42 AM
Focus Area Tags: Agriculture

Your water-efficient landscape doesn’t have to be barren

Volunteers rate the landscape plants during the Fall Open House at the South Coast Research and Extension Center in August 2022. All photos by Saoimanu Sope.

UC climate-ready landscape trials identify low-water yet attractive plants

Good news: roses can be a part of your water-efficient landscape. Lorence Oki, UC Cooperative Extension environmental horticulture specialist in the UC Davis Department of Plant Sciences, identified rose cultivars that remain aesthetically pleasing with little water.  

Oki is the principal investigator of the Climate-Ready Landscape Plants project, which may be the largest irrigation trial in the western U.S., and the UC Plant Landscape Irrigation Trials (UCLPIT), the California component of that project. These projects evaluate landscape plants under varying irrigation levels to determine their optimal performance in regions requiring supplemental summer water.

“There are some assumptions that pretty plants use a lot of water, like roses,” Oki said. “Everyone thinks they need a lot of water, but we've found some that don't, and they still look great. A water-efficient landscape doesn't need to look like a Central Valley oak-grassland in the summer. It can look really attractive.”

In 2021, Oki's team at UC Davis identified Lomandra confertifolia ssp. pallida "Pom Pom" Shorty and Rosa "Sprogreatpink" Brick House® Pink as two of the best low-water plants in the trial. 

An Austin Pretty Limits® Oleander growing in the 3-meter spacing deficit irrigation plot in the 2022 landscape irrigation trial at the South Coast Research and Extension Center.

“The useful tip or information that is shared at the end of each trial is the selection and designation of plants as Blue Ribbon winners. These are the plants that looked good with an overall rating of 4 or higher throughout and were on the low (20%) water treatment,” said Natalie Levy, associate specialist for water resources, who manages the project at the UC ANR South Coast Research and Extension Center.

How plants earn a blue ribbon

Each trial year, the selection of new plants is based on research recommendations and donated submissions from the nursery industry. The landscape plants are trialed in full sun or 50% shade cover.

Irrigation treatments are based on the rate of evaporation and plant transpiration (evapotranspiration) measured through a local California Irrigation Management Information System (CIMIS) weather station that provides a reference evapotranspiration (ETo) rate.

Three levels of irrigation are provided to the plants equal to 20%, 50%, and 80% of ETo. The volume of water applied is the same at each irrigation based on soil characteristics, but the interval between applications varies with weather and the treatment. Using this method, irrigations for the 20% treatment are less frequent than the 80% treatment.

“The 20% treatment during the 2022 trial was irrigated an average of once per month while the 80% treatment was irrigated weekly,” explained Levy.

During the deficit irrigation trial, monthly height and width measurements are taken to determine the plant growth index. Monthly qualitative aesthetic ratings on a scale of 1 to 5 are determined for foliage appearance, flowering abundance, pest tolerance, disease resistance, vigor and overall appearance.

A second round of flowering abundance and overall appearance measurements are also taken to capture more of the blooming period. For example, UCLPIT identified in the 2020 trial at South Coast REC that the "Apricot Drift" rose had a mean overall appearance score of 3.5 out of 5, deeming it “acceptable to very nice” and a low water use plant within the Water Use Classification of Landscape Species or WUCOLS guide.

Project expands options for landscape planting

Nathan Lo, staff research associate, and Natalie Levy take monthly plant growth measurements (length, width and height) of the Center Stage® Red Crapemyrtle.
While attending UC Davis as a master's student, Karrie Reid, retired UCCE environmental horticulture advisor for San Joaquin County, assisted Oki with landscape water conservation research. The landscape plant irrigation assessments were initiated at UC Davis in 2004 and the UCLPIT project, now in its 20th year, originated from her master's thesis project from 2005 to 2007. A CDFA grant supported duplicating these fields at the South Coast REC in 2017.

“(WUCOLS) only has 3,500 plants in it. There are guesses that there are close to 10,000 cultivars in urban landscapes in California, if not more,” said Oki. “WUCOLS also didn't have numerical ratings. Instead, you'll see verbal ratings like ‘low water use' or ‘high water use.'”

The UCLPIT project has not only developed numerical recommendations for irrigation, but it has also added new landscape plants that are compliant with California's Model Water Efficient Landscape Ordinance. In fact, UCLPIT's data is one of the few sources that can be used to supplement WUCOLS.

Geographic diversity of trial sites adds to knowledge base

In addition to UC Davis and South Coast REC in Irvine, the trials have expanded beyond California as the Climate-Ready Landscape Plants project and is in progress at Oregon State University, University of Washington, University of Arizona and Utah State University thanks to a USDA/CDFA grant awarded in 2020.

Lloyd Nackley, associate professor of nursery production and greenhouse management at Oregon State University, is the principal investigator of the trial in the Portland metro area, which is entering its third year.

“People know that there are drought tolerant plants, but there are many. We're trying to highlight lesser known or newer varieties. And even though the trial is three years, most gardeners would hope that their garden lasts longer than that,” said Nackley.

One of the observations that Nackley recalls is of the Hibiscus Purple Pillar plant. Unlike the trial at South Coast, the Purple Pillar did not perform well in Oregon in the spring.

“It wasn't until August that we saw the plant bloom and begin to look like what we saw from South Coast in April,” Nackley said.

Jared Sisneroz, a research associate from UC Davis, uses a LI-COR instrument to measure the stomatal conductance of a leaf on an Oso Easy® Urban Legend® Rose plant.

Ursula Schuch, horticulture professor and principal investigator of the trial taking place at the University of Arizona, was also surprised at the range of performance among different plant types and the effects of irrigation, heat and temperature.

“This research will reassure green industry professionals that they can stretch their water budget to successfully cultivate more plants, watering them according to their needs instead of irrigating every plant according to the highest water-using plants,” said Schuch.

Although research is only conducted in the West, the hope is that there will be trials in other regions of U.S.

Doing so would yield comprehensive information about the plants and their performance in different climates. As extreme weather events persist in the U.S., disease pressure and risks do too. Trials throughout the country would provide location-specific data regarding disease susceptibility. 

To learn more about the UCLPIT research project, visit https://ucanr.edu/sites/UCLPIT/

Posted on Tuesday, January 17, 2023 at 11:18 AM
Focus Area Tags: Environment, Natural Resources, Yard & Garden

Plant Suggestions for your Rain Garden

Last week in this column we suggested creating a swale in your home garden to capture rain and practice effective water conservation. If you have been inspired to start planning a swale, you may be looking forward to the fun of selecting plants for this...

California fuchsia shrub, Jeanette Alosi
California fuchsia shrub, Jeanette Alosi

California fuchsia shrub, Jeanette Alosi

St. Catherine’s Lace buckwheat in bloom, Jeanette Alosi
St. Catherine’s Lace buckwheat in bloom, Jeanette Alosi

St. Catherine’s Lace buckwheat in bloom, Jeanette Alosi

Yarrow-achillea millefolium whilte, Brent McGhie
Yarrow-achillea millefolium whilte, Brent McGhie

Yarrow-achillea millefolium whilte, Brent McGhie

Hummingbird-sage, Brent McGhie
Hummingbird-sage, Brent McGhie

Hummingbird-sage, Brent McGhie

Eva Case' coffeeberry, Jeanette Alosi
Eva Case' coffeeberry, Jeanette Alosi

Eva Case' coffeeberry, Jeanette Alosi

Redbud in bloom, Jeanette Alosi
Redbud in bloom, Jeanette Alosi

Redbud in bloom, Jeanette Alosi

Ceanothus 'Concha,' Jeanette Alosi
Ceanothus 'Concha,' Jeanette Alosi

Ceanothus 'Concha,' Jeanette Alosi

Posted on Friday, December 16, 2022 at 5:00 AM
Focus Area Tags: Yard & Garden

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