Agri-Fos Control for S.O.D in CA?

Jomo

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I've got 4 mature coastal live oaks in close proximity to each other. Two of which are lightly infected with S.O.D.(Phytopthora ramorum). The other two appear to be healthy.

Have any of you had any hands on success whatsoever treating S.O.D. with Agri-Fos fungicide systemically in California?

Thanks,

Jomo
 
No, but other Phytopthora in oaks are routine to manage in oaks elsewhere by cleaning and heating and soil replacement, and phosphite.
 
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  • #3
Thanks Guy.

Agri-Fos is of course a phosphate derivative labeled for use to treat Phytopthora ramorum in CA. However only minimally as a curative in lightly infected Q. agrifolia, and more of a preventive in healthy oaks in that particular species.

Hopefully some of the NorCal Bay Area lads'll chime in since S.O.D. originated in Marin County in the early 90's.

Jomo
 
From my understanding it's pretty much the primary treatment for infected or susceptive oaks with p. ramorum. We had some success around 2002/03 in treating a very large q. agrifolia which is still around. The tree had somewhat advanced signs of the pathogen i.e. red gummosis, charcoal fungus, evidence of bark beetles, bark sloughing etc. etc. The tree is still standing FWIW.

jp:D
 
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  • #6
Thanks guys.

I'm going to give a mixture of Agri-Fos n PentraBark a try as a trunk spray.

More of an R&D project that I'll only charge the client for materials.

S.O.D.'s pretty much a death sentence here locally, unfortunately.

Jomo
 
I've had the best luck with soil injection in general but haven't used that method with P. cactorum.
Here's one that isn't working out.
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  • #8
Thanks Willie.

That tree's a goner IMO.

The pathologists say that too much water renders the tree more susceptible to SOD. So your client's lawn being over the tree's root system may be why the tree got nailed so badly?

Jomo
 
Yeah, I had them move the irrigation a couple years ago, it had been hitting the trunk daily in the summer and puddling at the base, they corrected both issues but it appears too little too late.
 
The soil looks pretty bad. Can't ignore the bottom half of the tree (the roots).
 
I would do the agriphos. It's a decent prophylactic as well as a fertilizer to beef up defenses. I was working in Marin Co during the outbreak and development......nowadays. we have a 30 foot CLO on the Presidio with SOD.....I airspaded it and back filled with ammendment. Two years ago. Still standing .....it looks lighter in green than it's twin next to it which tests negative for SOD....15 feet away....

Keep the tree healthy and let it fight back.....barring some public safety concern of suddenly falling tree....
 
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  • #14
Thanks for the feedback Bodean, I appreciate it.


LIFE CYCLE/BIOLOGY OF PATHOGEN
Phytophthora species are funguslike organisms, related to algae, which occur worldwide. They are water loving and produce plentiful spores in moist or humid conditions. Most known Phytophthora species are soil-dwelling root pathogens; however, P. ramorum acts primarily as a leaf pathogen. In California, it thrives in the coastal tanoak/redwood forests and oak woodlands within the fog belt. Nurseries outside of these cool, moist areas often create microclimates that mimic an environment supportive of P. ramorum and allow it to grow and spread far from the coast.

While most nonoak hosts are not killed by the disease, they do play a key role in the spread of P. ramorum, acting as a breeding ground for inoculum that can spread through water, wind-driven rain, plant material, or human activity. Oaks are considered terminal hosts, since the pathogen does not readily spread from intact bark cankers; they become infected only when exposed to spores produced on the leaves and twigs of neighboring plants.

Research in California forests has shown that the greatest predictor of P. ramorum canker on oak is the presence of California bay laurel (Umbellularia californica). Pathologists believe P. ramorum drips or is blown down onto oak trunks from neighboring bay leaves when it rains. Once on the oak trunk, P. ramorum uses natural openings in the bark to colonize the bark tissues, killing cells and clogging water and nutrient transport vessels.



Jomo
 
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  • #15
Another important aspect of combating P. ramorum are Camellias and Rhododendrons being host plants that spread the disease. So if your clients with susceptible oak species have either of these plants on their properties? Removal of them ASAP is the wise recommendation IMO.

Rhododendron Flower Buds
Steve Tjosvold

Question: What is the latest on Phytophthora ramorum in nurseries?

Answer: Phytophthora ramorum, the pathogen that causes Sudden Oak Death, caused extensive natural infection of Camellia flower buds in field experiments conducted in Santa Cruz County. Infection of Rhododendron flower buds also occurred but to a much lesser extent than in Camellia.

Question: Why is this important?

Answer: Camellia and rhododendron are the two most important nursery host plants of P. ramorum, accounting for the majority of detections in infested commercial nurseries. Until now, detection of this disease on these nursery hosts has focused on identifying leaf infections because we did not know about the possibility of flower bud infection. In fact, in our field observations, flower buds could be infected, but no leaves were ostensibly visible with symptoms. Furthermore, flower buds may be an important source of inoculum and pathogen spread in nurseries. Flower bud parts are readily susceptible to infection, they can produce copious propagules, and infected whole flower buds or parts eventually fall from the plant and could be blown in the wind to other parts of the nursery or become a suitable source of long-lived propagules in the soil or other leaf litter.

Jomo
 
In Oregon the control measures are clear cut so many feet around infection and burn it
 
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  • #18
The tell tale sign of SOD is the bleeding black exudate that runs out of the trunk wood Sean.

Just got the go ahead to treat the two infected CLO's with Agri-Fos mixed with PentraBark today, as an R&D project.

These are lightly infected trees, both in the 48" DBH range.

I'll be taking pics and posting the results here once the owner's given me permission to do so, which I expect they will, considering my time on the project will be pro bono.

Jomo
 
For some disease, Red flowering currant/ Ribies (IIRC) is an intermediary host. The gov't spend a lot of time trying to eradicate the ribies, which doesn't work. I thought it was SOD.

We have some in Sammamish WA at nurseries, and at a neighboring county to mine (Kitsap).
 
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