FYI:

The Asian ambrosia beetle:

I don't know the origin of the information in the email below that was
forwarded because of the quotes, etc. From my experience which is about 10
years working with the beetle in the field, I think the email contains some
misinformation.

AAB are attracted to traps baited with ethyl alcohol in the spring and early
summer and the trap numbers correlate very well with attacks on trees most
of the time. However, the AAB emergence can be quite localized as to timing
of emergence from overwintering. In the mid summer to fall and winter, trap
catch with ethanol does not adequately represent the AAB present, even
though they don't usually attack nursery stock at this time. Why they don't
respond to traps as well then is anyone's research project.

AAB may overwinter in the duff, but I think that is someone's guess and
seems foolish from my view for the beetle to do. I know for a fact that all
life stages overwinter in the galleries of attacked trees in north Florida
and have survived winters in the trees very well with temperature below 19
degrees F.

AAB usually attack trees that are stressed in some way. Under nursery
conditions this appears to be from unbalanced root to shoot ratios with the
actual physiological mechanisms unknown. The trend toward growing larger
trees for instant landscapes is contributing to the AAB problem in the
nursery and landscape. There appears to be a threshold of tree
susceptibility that can fluctuate in time for individual trees or for
species of trees. Most trees that are attacked and appear ostensibly healthy
are usually exotic species and/or ones delayed in phenology.  The phenology
variable is of secondary  importance to the primary stress factors. In the
nursery, AAB will respond to such trees differently. For example, Bradford
pears will be attacked in a very aggregated or patchy distribution with few
trees coming under attack. However, each tree will have a large number of
attacks. In contrast, with Drake elms, most of the trees will be attacked
with only a few attacks on each tree, again suggesting the variable
thresholds. With dogwood you get a decidedly different response depending on
time of year and location. AAB often attack dogwood mistakenly and are
"pitched out"- southern pine beetle term) i.e., drown,  in north Florida.
But bring a dogwood in to north Florida from TN and place it in the field at
the same time and the tree from TN will be attacked successfully. Again,
suggesting a variable threshold in the tree's condition that may be
mitigating attacks.   With all trees we recommend leaving the attack trees
on site for 30 days before removal to reduce the number of total trees
attacked. This should be coupled with insecticide applications (see below).
We have not observed brood out of first generation trees to attack nursery
stock at their emergence.

An analogy: The beetle and the tree are in effect talking to each other
around the question of attack or not. That is the beetle should not attack
trees that are unsusceptible for attack and brood production and the tree
should not want to be wounded even if it can prevent successful attacks by
drowning the beetles once they penetrate. The tree should do best if it
clearly indicates it true condition to the beetle when it is above the
threshold of susceptibility and lie or confuse if below the threshold, if it
can.  Dogwood apparently speaks a "foreign" language when it resides in
north Florida and suffers the consequences.

We have recently made some significant and very exciting breakthroughs on
manipulating AAB behavior. We are presently exploiting these tools to better
understand the interaction of AAB with its hosts and other important
questions. We have found that 4-5 or more AAB attacks per tree with a
caliper of <3 inches is enough to kill most of these trees.   I will be
reporting the results of some new more definitive insecticide evaluations at
the SNA meeting in Aug.  At this point our results indicate that Onyx
(bifenthrin-FMC) at the rate of 32oz/ 100gal  will prevent most AAB attacks.
Lower rates provided some degree of prevention but were inconsistent.
Talstar F at 40oz/100 and Thiodan were also effective, however, Thiodan
efficacy was variable, as was Dursban.  WHAT DID NOT WORK: Tame, Orthene,
Tempo.

I hope this helps clarify some information.
Regards,
Russ

Dr. Russell F. Mizell, III
Professor of Entomology & Director
Southern Region Pest Management Center
University of Florida
155 Research Rd
Quincy, FL 32351
850-875-7156 - Ph.
850-875-7148- Fax
[log in to unmask]


-----Original Message-----
From: Osborne, Lance S. [mailto:[log in to unmask]]
Sent: Thursday, May 27, 2004 7:44 AM
To: [log in to unmask]
Subject: FW: Another Asian beetle causing problems to nursery, fruit, and
other growers


Funny this had to come via New York and a plant pathologist at that.

Lance.

-----Original Message-----
From: Daniel Gilrein [mailto:
Sent: Wednesday, May 26, 2004 10:04 PM
To: Ornamental Entomology
Subject: Fwd: Another Asian beetle causing problems to nursery, fruit, and
other growers

Something that came via our pathologist, on e-mail. Most of you probably
already know about this. I think the source is Faith Campbell (Scott Ludwig
probably knows for sure!):

___________________________________

The Asian ambrosia beetle, identified as Xylosandrus crassiusculus
(Motschulsky), was first detected in the continental United States 30 years
ago near Charleston, South Carolina.  It apparently has spread throughout
Florida, north to the lower Piedmont region and coastal plain of North
Carolina; and west through Louisiana into eastern Texas.

  In the Gainesville, Florida area it is abundant in urban, agricultural,
and forested areas.

Floridians have observed damaging attacks on potted saplings of Shumard oak
(Quercus shumardii Buckl.) and Drake elm (Ulmus
parvifolia Jacq. cv. Drake).   It is considered to be a potentially
serious pest of ornamentals and fruit trees throughout Florida. Growers in
South Carolina see it on peach trees.

In Texas, according to a story that appeared earlier in May, "a good part of
the $225 million East Texas nursery industry is at risk ", along with pecan
orchards, redbud, ornamental pears and red oaks.

Numbers of the beetle are reported to be higher this year than in the past,
in both Florida and Texas.  No one knows why the insect has made such an
impact this year, but a Texas Cooperative Extension integrated pest
management specialist, Dr. Scott Ludwig, is quoted as suspecting that mild
winters have played a big role. (The adult beetles overwinter in leaf
litter.) ...

Ambrosia beetles are so named because they cultivate the ambrosia fungus
inside the tree. ... The fungus plugs up the tree's vascular system ...  Dr.
Ludwig has launched a two-fold emergency program: USDA is funding tests of a
new preventative trunk spray.  A trapping survey is under way to find out
just how widespread the Asian ambrosia beetle is in eastern Texas.

Once a tree is infested, no chemical controls will save it.  Juvenile trees,
up to three years old, are usually killed.  Mature trees are more likely to
survive the infestation but may serve as staging base for the beetle to
attack nearby younger trees. For this reason, the general control strategy
is to cut down and destroy any infested trees immediately. "The quandary
comes when a favorite mature tree is infested,"Ludwig said. "No one wants to
cut down and burn an otherwise healthy tree, but not doing so could endanger
new trees in the area."

***********************

--
------------------------------------------------------------------------
Daniel Gilrein                   Long Island Hort. Res. & Ext. Center
Extension Entomologist           3059 Sound Ave.
Cornell Cooperative Extension    Riverhead, NY  11901 USA
       of Suffolk County
------------------------------------------------------------------------