That should read 'Raffaelea', not 'Raffalea'

Jason

Oh, no!!!!
Laurels are host to palamedes (persea) and spicebush (sassafras and lindera) swallowtails!! If laurels are wiped out, so will two of our most beautiful butterflies!
This is beyond horrible!!
I didn't see camphor trees mentioned. Since they're Asian, they might be resistant to the disease, like Asian chestnuts don't get chestnut blight. They're used by spicebush swallowtails in some areas, and I guess palamedes swallowtails might use them.
Sherry

Not another disease!

This one could mean the end of Avocado cultivation in the New World, too.

Resin

PS original text repeated below, converted to sentence case for easier reading!

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Just a brief update on a new disease killing members of the Lauraceae in the U.S.:

In 2002 an Asian species of ambrosia beetle (Xyloborus glabratus) was found near Port Wentworth, Georgia (near Savannah). It was soon discovered associated with dying Red Bay (Persea borbonia) trees in the vicinity. Closer inspection revealed the presence of a fungus (Raffalea species) similar to the dutch elm disease fungus. The fungus is very aggressive and can kill entire trees in a couple of months. The beetles are the vectors and are likely infecting trees while feeding on twigs on the outer portion of the crown. The fungus rapidly invades the xylem and plugs up the vascular system. Once a tree succombs, large numbers of ambrosia beetles attck them (possibly for brood trees) and are loaded with inoculum to move to the next tree. Symptoms of the disease include wilting, leaves turn brown and do not fall off the trees. Under the bark a dark colored streaking is evident on the wood.

Current distribution includes coastal areas of South Carolina, Georgia and northeast Florida (approximately 31 counties). However, new counties are being detected weekly and the disease is spreading very rapidly via the beetle vectors at a rate of at least 20 miles per year. It is likely that humans are aiding in its dispersal by moving firewood of infected trees to new areas.

The host range is still being determined, but all members of the Lauraceae seem susceptible. So far it has been found in Persea, Sassafras, Lindera and Litsea in the wild.

The impact of this disease is huge. Most stands surveyed have at least 95% mortality after the disease moves through. Unfortunately it looks like Red Bay will be extirpated from most areas. Time will tell for other species.

I am working with the U.S. Forest Service and others to see if the very few trees remaining have any resistance to the disease. Many other studies are underway to try to reduce the impact of this disaster.

If you suspect the presence of this disease, please contact your county extension agent or let me know and I can give you advice on who to report it to.

I will keep you posted.

Jason Smith, forest pathologist, University of Florida

Spellcheck for info searches:

Xyleborus glabratus

Thanks for taking care of that Resin. I wrote that fast and didn't notice the error.

Yes, avocado is susceptible, as is Cinnamomum. The jury is still out as to whether or not they will be so widely infected in nature as Red Bay though. So far, one plant of avocado has been found infected naturally in the field. It was planted there to see what would happen. It is important to note that avocado isn't hardy in the areas where the disease is right now. As it moves south into south Florida, then avocado will be at risk. The same is true if it gets to California, Hawaii or southern Europe.

Hi Jason,

A fungal query - I was doing a little looking around on the web about it, and most of the sites I found listed the fungus as an undescribed Ophiostoma species - has it been reclassified in Raffaelea subsequently?

Resin

Raffaelea is an anamorph (asexual stage) of Ophiostoma. Since this fungus has yet to produce a sexual stage in culture or in nature, it should be referred to by its anamorph name. Unfortunately, this is the standard for mycology - where the sexual (syn. perfect) and asexual (syn. imperfect, anamorph) stages are classified differently. However, if both stages occur, it is correct to use the sexual stage name for general usage.

It's sad to hear about the Redbay and Sassafras, but it wouldn't bother me if it did affect Camphor trees. Camphor trees are an invasive weed here.

Except that Camphor may be the only tree left to support the Spicebush butterflies!

Susan

Not another disease... Chestnut blight, Dutch Elm disease, sudden oak death and oak wilt, hemlock wooldy adelgids, emerald ash borer, beech bark disease... and now another one... argh!!

Salicaceae, big change from MN to FL, eh? The trees that I traded you for are all still alive (Loblolly & Himalayan W pines), and my Longleaf pines seedlings too, tho they're shivering now w/avg daily temps about 15F (-10C) and brutal winds for the last week.

Regarding the fungus, this is just anecdotal & prb'ly has nothing to do w/Raffalea, but I noticed when I lived in SW VA that Sassafras was very succeptable to some kind of ailment -- visually like a fungus blight. It had pretty much wiped out the understory of Sassafras seedlings that were very common in the forest when I first moved there. Here in MD seedlings/sprouts are much less common than 20 yrs ago too. I never read/heard of any official reference to Sassafras problems, but they've greatly declined in localized areas I've seen.

Hey Jason, I didn't realize that "salicaceae" was you!

It's a small webernet.

-Jeff from DOF Forest Health

While I'm replanting my woods due to disastrous hurricane damage, I've decided to plant as many different types of laurels as I can. I've ordered persea/machilus thunbergii and lindera strychnifolia from Woodlanders in Aiken, South Carolina and lindera erythrocarpum and l. praecox from Forest Farm in Williams, Oregon. The ones from Woodlanders are supposed to be propagated there, and I'm sure Forest Farm is the same - I don't think any of these plants are imported, with the possibility of importing more Asian bugs.
For me to be planting anything from Japan or China is quite a departure! I generally only plant native plants or plants that are native to areas real close to my area - I don't even plant cultivars, just the species. My 5 1/2 wooded acres are full of Chinese privet, Japanese honeysuckle, and Japanese climbing fern, so I can see for myself that many Asian species are much tougher than our native counterparts - somehow, my area has escaped kudzu. I pull these invaders all the time - you should see some of the deformed trunks on dogwood trees cause by Japanese honeysuckle twining around the trunk like a boa constrictor! :( But I imagine that the only hope we'll have of growing a laurel that's too tough for the Asian beetles to bore or at least too tough for them to completely exterminate is with Asian laurels. If I can grow a laurel that palamedes and/or spicebush swallowtails will lay eggs on, whose leaves the caterpillars can eat and grow successfully to maturity on, then at least there'll be some tough Asian laurels that might not get the beetles and ensuing fungus. If it ever looks like any of my foreign laurels are becoming invasive, I'll certainly get rid of them.
Woodlanders was out of l. fragrans or I would have gotten that one, too. If anybody can send me seeds of foreign laurels or give me the name of any nurseries that carry one or more of them, please let me know.
Most butterflies, including palamedes and spicebush swallowtails, are very 'family specific' as to what they'll lay eggs on - I've never found a caterpillar on anything but persea and sassafras. I've recently planted a native American spicebush, but my spicebush swallowtails apparently don't know to use the plant they were named for - they think they're sassafras swallowtails! :)
Sherry

Is the fungus itself exotic, or was it already around before the beetle arrived?

Beng,

Yes, it is a big adjustment - but I like it! Glad to hear the pines I sent you are still alive...

Jeff,

Yes, I have been an infrequent poster on GW for sometime now....I thought it would be a good place to alert people about this disease problem...

Carrie,

We don't know if the fungus is native or exotic. However, we do know that the beetle vector is exotic and the fungus would seem to have a hard time being dispersed without it. Thus, the current belief is the fungus came with the beetle.

Hello; I am an undergraduate student at the University of North Carolina at Wilmington with the intention of majoring in biology or marine biology. I am currently trying to determine if Laurel Wilt disease has traveled to Bald Head Island, in North Carolina. I have not had much experience in this area, so any suggestions you might have for identifying the disease on Red Bay trees would be most helpful. If i find any symptoms, I will report back here and let you know. Also, did you notice a decrease in the rate of mortality during the winter months, or do the vector beetles not become dormant? Thanks for your help,

-Robert

Hopefully, somebody who lives on or travels to Bald Head Island will report back to you - please report back to us any information you have.
I wish you'd make this your main field of study! This insect/disease could be the end of two of our most beautiful swallowtails, not to mention the loss of some beautiful laurels.
Sherry

Robert,

So far, there have been no reports from North Carolina. It is found only in SC, GA and FL. If you would like a copy of the current distribution map, please send me an e-mail.

Jason

YIKES!!! I have (had) two bay laurel trees in pots in my greenhouse in upstate NY, both over three feet tall and one I had for ten years from a cutting. They both got severely browned leaves in a gradual wavy pattern from the top down about two months ago, before being moved outside, while the greenhouse was still closed up for winter (doors insulated, bubble wrap in the glass, etc, the only access a door from my house). I thought it was stress from an electric heater overwarming them, though nothing else had been affected. Vascular system is definitely dying back despite cutting back to live wood. A few new leaves have appeared on one, but even those appear to be succumbing shortly after emergence. They're both outside now. What should I do? No sign at all of insect damage. I was advised today at a greenhouse to unpot them, check the roots and if they appear dead, to write them off. I have tried cuttings but have never had success starting cuttings from bay; it appears alive but just won't form roots and never seems to grow. I don't want to increase the risk of disease; please advise how best to dispose of them, and who to contact!