SOD Blitz Results 2014 – Press Release
SODMap Project
SODMap Heat Maps
How can I tell if my trees have SOD?
Sudden Oak Death can kill oak and tanoak trees but it vectored, or spread, primarily through the leaves of California bay laurel. You can see what SOD symptoms on bay leaves look like in this picture. In the spring of each year the lab hosts the SOD Blitz Survey Project where you can learn to spot SOD infections, collect leaves on your trees, and have them tested for SOD.
Are there any SOD meetings or workshops?
Yes! There are free meetings and workshops that you can participate in throughout the year:
You may also want to check out the SOD Blitz project webpage for more information.
How can I get my trees tested for SOD?
Our lab does not provide a year-round SOD testing service. However, each spring we conduct the SOD Blitz Survey Project that trains “citizen-scientists” to collect leaf samples in their communities and provides free testing in our laboratory. You might also be interested in seeing how we test for SOD.
Are there any treatments for SOD?
There are a number of things to keep in mind regarding SOD disease management, you might want to check out these two guides: What to do before SOD arrives in your area and What to do after SOD arrives. There are also preventative chemical treatments available and SOD treatment training workshops conducted at UC Berkeley.
SOD: Cleaning Tools & Equipment
Topic:
Cleaning tools in SOD-infested areas.
Problem:
Can tools become infectious when used on trees infected by SOD? Yes, in particular when dealing with infected foliage, infested soil, and marginally with infected wood. The risk of spreading SOD is higher if soil or infected leaves are present on tires, shoes or tools. Wood is generally, not as infectious
Recommendation:
Differently from other pathogens which produce invisible microscopic and often sticky spores that can remain viable even on apparently clean tools, the SOD pathogen produces spores that are normally lodged in plant debris, organic matter, and plant or soil residue.
In order to clean your tools, shoes, and vehicle tires you can follow this two-step procedure:
- Clean all visible organic residue, plant tissue or soil from the tool. A wire or plastic brush is generally effective. Removal of all visible debris will eliminate 99% of all infectious propagules.
- Washing with a disinfectant that will kill any remaining spores. We have found that 70% ethanol, diluted bleach, and Lysol brand disinfectant are all effective. Lysol, which contains benzalkonium chloride, a powerful and effective antiseptic, is the product we use most often as ethanol tends to be the most expensive of the three, and bleach can cause corrosion of metal tools.
Note: it is important to ensure all parts that came in contact with infected plant material are visibly clean and that no organic matter remains. This is particularly crucial for tools like chainsaws or machinery like chippers. The physical cleaning step (above) is critical, and can be effective even without washing although the application of a disinfectant may help). Washing first and then cleaning will be ineffective. Always wear safety glasses and protective equipment as recommended by the manufacturer and always follow the manufacturer’s directions, restrictions, and precautions on the product label.
Research behind the Recommendation:
To test the effectiveness of tool cleaning on the transmission of P. ramorum, a chainsaw and handsaws were “contaminated” with SOD-infected wood chips and saw dust. The saws were treated by different methods in an attempt to “decontaminate” them including, removing the visible organic matter with a wire brush or brushing followed by a disinfectant rinse. The disinfectants used were 10% ethanol, 5% bleach, and lysol (diluted as instructed on the label).
After cleaning, the saws were examined under magnification, any remaining bits of plant or organic matter plated on selective agar Petri dishes. The percentage of infectious propagules that grew on the agar plates is graphed below. Click to rebigulate the pdf.
Links and References:
- Protecting trees from SOD before infection
- SOD Sanitation Guide
- What to do after SOD arrives in your area.
Disclaimer: Mention of any company, trade name, or commercial product does not constitute endorsement by the University of California or recommendation for use. Always follow the manufacturer’s directions, restrictions, and precautions on the product label.
SOD Community Meetings
What is Sudden Oak Death?
SOD is an exotic disease caused by the microscopic pathogen Phytophthora ramorum, estimated to have been introduced into California 20-25 years ago from unknown region of the world.- P. ramorum was unwittingly introduced into California’s natural landscape when infected ornamental plants, such as Rhododendrons and Camellias (which carry the disease), were outplanted into the environment. On many ornamental plants, as well as many native forest plants (including California bay laurels and tanoak), the pathogen causes a disease called ramorum blight. Ramorum blight is a foliar disease that often supports pathogen sporulation and spread, as the spores build up on the leaves and twigs of these hosts which can then be transferred to nearby oaks and tanoaks, causing sudden oak death. Ramorum blight is rarely lethal.
- In California, foliar infections on Bay Laurel leaves are mostly responsible for spreading the disease. Oaks and tanoaks are infected when in proximity of bay laurels. Oaks only get a stem infection; tanoaks can develop both stem
and a foliar infection. Tanoaks are the only tree species that can spread the the disease and die from it as well. When P. ramorum infects oaks and tanoaks it destroys the cambium under the bark and effectively girdles the tree. Girdled trees are doomed, but can survive for 1 to 5+ years thanks to stored resources and their natural tolerance to drought. - Besides Tanoaks, California Coast Live Oak, Black Oak, Shreve’s Oak, and Canyon Live Oak are known to be infected by P. ramorum. Oaks are not infectious in nature and do not spread the disease further, but oak wood may be infectious if carried to an uninfested area.
- P. ramorum can infect leaves and trunks of it’s hoasts without the need for wounds, but it does require rainfall and temperatures between 60 and 80F (25 to 27C). As a result most infections occur in the rainy season and in particular when spring temperatures rise (mid April to June).
- Yearly infection levels will depend on the presence of rainfall in the Spring; while tanoaks and bay laurels are infected yearly, oaks are normally infected only in years with abundant Spring
percipitation. - P. ramorum is dispersed aerially usually at short distances 100 yrds (100m) or less, but occasionally up to 1-2 miles (1.7-3.5km).
- Infectious airborne microscopic structures known as sporangia are produced during rain events on plant surfaces, primarily leaves, and can also accumulate in soil and stream water.
- Besides the natural spread of the pathogen, movement of infected plants or plant parts, soil, and water may lead to new infestations. Soil and plant material on tools and equipment may vector the disease.
- During dry periods, the pathogen survives within infected plant tissues, and by producing a thick walled resting structure called a chlamydospores. As a result SOD remains persistent in any site, but oak infection varies as it requires high infection levels of bay laurels.
