- Author: Sonia Rios
The California Avocado Commission is joining forces with Kevin Turner, UC Cooperative Extension goldspotted oak borer (GSOB) program coordinator (http://ucanr.edu/sites/gsobinfo/) in producing and distributing a number of roadside signs to help control the movement of pest infested firewood.
They are asking for avocado grower's participation in areas that are susceptible to the GSOB and/or the Polyphagous Shot Hole Borer (PSHB). GSOB susceptible areas include oak woodlands and forests while PSHB environments include avocado groves. Some of these susceptible locations are primarily focused in the Fallbrook, Escondido, Valley Center, and Alpine areas. Eventually signs will be developed that will feature both the GSOB and the PSHB and discourage movement of oak and avocado wood.
The signs can go in a variety of frame designs. Most signs are 4' x 8'and are normally inserted into a redwood frame, but can be as simple as posts and a piece of exterior plywood onto which the thin aluminum sheet sign can be attached. The signs should be placed visibly along major roadways or busy streets.
If you would like to participate by permitting signs to be placed on your property along major streets, please contact:
Kevin Turner, GSOB Program Coordinator, UCCE/UCR
kevint@ucr.edu
951-827-5115
951-452-6427 cell
- Author: Ben Faber
Polyphagous Shot Hole Borer can go to over 100 and counting hosts, but the Fusarium that the ambrosia beetle carries can not reproduce on all tree species. It is this fungus that ultimately kills the tree. There are now though thirty-seven hosts on which the beetle will attack and the Fusarium will grow. Here is the current list, 14 of which are California natives:
Known Suitable Reproductive Host Trees:
*Native species to California
- Author: Ben Faber
From The Packer:
South Florida university researchers are using dogs and drones to sniff out a disease that's killing the region's avocado trees.
The Florida International University researchers are sending dutch sheppards and belgian malinois into avocado groves to locate trees infected by the lethal laurel wilt disease, which is spread by the redbay ambrosia beetle.
Detection is a major problem and trees can start to wilt within two weeks.
By the time infected trees are detected, the fungus has likely spread to nearby trees via root grafting, said DeEtta Mills, a biological sciences professor.
She and Kenneth Furton, a university provost and forensic chemist, are leading research that trains and deploys five dogs into Miami-area groves.
Drones flying above the groves can detect symptomatic trees, which signal researchers to direct the dogs to infected areas.
The dogs run through the groves and with their powerful noses, have been 90% accurate in locating infected trees, Mills said.
Because of permitting paperwork delays by the Federal Aviation Administration, the researchers haven't been able to use the drones.
The researchers hope to receive approval for drones by August and are relying on growers to point them to infected trees.
The drones provide higher accuracy and can better cover larger areas because running the dogs too long can overheat them and wear them out, Mills said.
Their heavy panting can dull their sniffing senses so after about 20 minutes, the researchers return them to kennels in air conditioned vans, Mills said.
The dogs are trained with diseased wood and infected tree samples detected by the dogs are sent to researchers who examine DNA to verify contamination, she said.
“These dogs, they love to do this and it's amazing to watch them,” Mills said. “These ‘girls' come out of the kennels of the van and ask us where we would like to send them and what we would like them to do. They're extremely highly-driven dogs. If we can get permission to use the drones, it will help us identify areas we need to go in with the dogs and help us verify infection much faster so the dogs won't have to cover as much ground.”
Canine detection is another way of helping save the state's multi-million dollar avocado industry and ultimately, the North American industry.
Florida growers have lost about 4,000 of nearly 800,000 trees and the disease has spread throughout the Mid-Atlantic and into Mississippi.
If it travels farther west, the dogs and drones detection system could also help growers in California and Mexico protect their much larger production, she said.
The Miami university is also working with University of Florida researchers and growers.
N.B. These techniques could also be used to trace Polyphagous Shot Hole Borer infested trees, as well.
- Author: Ben Faber
Polyphagous Shothole Borer which is an ambrosia beetle that normally feeds on dead trees is going after live trees - over 100 species including sycamore, alder and coast live oak. It also goes after avocado. The California Avocado Commission has sponsored the placement of traps that have lures for PSHB. The traps are near avocado orchards but also likely spots where they might show up, such as campsite where people would bring firewood that might be infested with the beetle. The map here shows where the traps are located and where PSHB have been trapped. There are also traps in Santa Barbara County which are not yet shown on this map.
- Author: Sabrina Drill
As discussed in previous issues of this newsletter, polyphagous shot hole borer (PSHB; Euwallacea sp.) is a new pest/fungal complex attacking a wide variety of host trees in Southern California, from avocado to common residential and street trees and native oaks and riparian species. The PSHB is morphologically identical to the tea shot hole borer, E. fornicatus, but a genetic analysis confirmed that this is a new species of ambrosia beetle. PSHB has been found to carry several symbiotic fungi, including new fungal species Fusarium euwallacea, andan undescribed Graphium species.It was first identified in 2003 in Whittier Narrows, an undeveloped riparian area in Los Angeles County, and was officially first linked to tree injury and mortality in a residential avocado in 2012. Since then, the pest complex, also referred to as Fusarium die-back, has spread throughout Southern California and is now present in Los Angeles, Orange, San Bernardino, Western Riverside, and San Diego counties. The population in San Diego County is a different genotype from that found in the rest of the region, possibly indicating a separate introduction. The pest/disease complex has caused significant impacts to the avocado industry in Israel, and is now spreading in commercial groves from Escondido to Fallbrook. It has caused injury and mortality of hundreds of ornamental trees in the urban areas, impacting roadways, botanical gardens, parks, and private residences, and impacts all major native riparian trees species. The official list of reproductive hosts, meaning trees that can support growth and reproduction of the beetles and fungi, includes 35 species with several having been confirmed in just the past few months.
The plant pathology, IPM, environmental horticulture, and natural resource management teams working on this pest at UCR and UC Cooperative Extension in San Diego, Orange, Los Angeles, and Ventura Counties have put together several useful tools that can help you manage this pest. These include a new field identification card set, a decision tree for tree removal, a guide to managing infested plant materials, and information about how to report an infested tree and how to collect samples for lab identification, as well as a continuously updated web-based map. You can find these at www.pshb.org.
To determine if your trees are affected by this pest:
- Look for a small (tip of a ball point pen) round entry/exit hole surrounded by wet discoloration of the outer bark
- Follow the gallery to look for the beetle (may or may not be present)
- Look for other hosts (Castor bean, sycamore, maple, coast live oak, goldenrain, liquidambar) showing symptoms of the beetle/disease
- Report suspect tree infestations to eskalenlab@gmail.com with the following information:
o Your contact info (name, city, phone number, email)
o Suspect tree species
o Description of suspect tree's location (and/or GPS coordinates)
o Description of suspect tree's symptoms
o Photos of suspect tree and close-up photos of symptoms
- If symptom photos and descriptions indicate it might be PSHB/FDB a field assessment may be needed or a sample can be submitted following detailed directions on how to collect and submit a sample for fungal confirmation at pshb.org.
To protect your trees, avoid movement of infested firewood and chipped material out of infested areas. Infested material should be chipped to under 1”, wrapped in clear plastic, and solarized on site for up to 6 mos (depending upon environmental conditions). Research is ongoing in the use of insecticides and fungicides, as well as exploration of the use of endophytic bacteria as a biocontrol agent. If you suspect that you have found this beetle or seen symptoms of the Fusarium dieback on your tree please contact the Ventura CE office, your pest control advisor or qualified arborist, or contact UC Extension Plant Pathologist Dr. Akif Eskalen by at akif.eskalen@ucr.edu. For more information visit www.pshb.org or http://eskalenlab.ucr.edu/avocado.html.
PSHB DAmage