GSMNP on alert for Emerald Ash Borer.

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KoutaR
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Re: GSMNP on alert for Emerald Ash Borer.

Post by KoutaR » Mon Aug 23, 2010 5:47 am

Will Blozan wrote:Probably a difference in vector density and mabye tree physiology. I did a study of BBD back in the late 90's in GRSM and the scale was rare in the low elevations and extrememly dense in the high elevations.
Will & James,

Those sound very logical causes to me. Do you know, why is the scale insect dense in the high elevations? Two possible reasons come to my mind:

1. The scale insect is native to Europe (correct me if I am wrong). The climate in the low elevations of GrSM is probably warmer than that in the natural range of the European beech. Perhaps the scale is adapted to climates more like those in the northeast US and in the high elevations of GrSM?

2. Are beech populations more dense in higher elevations? In the low elevations, where species diversity is very high, beech is probably more rare, and thus the scale would also be more rare.


It is interesting (and sad, of course), that so many exotic pests and diseases are so severe to American trees. There are chestnut blight, emerald ash borer, white pine blister rust, hemlock woolly adelgid, Dutch elm disease, beech bark disease, Phytophthora lateralis (for Port Orford-cedar in the west), ... In Europe Dutch elm disease has almost wiped out Ulmus minor, but I do not know any disease fatal to European trees which would be native to North America. This is almost like with Europeans and native Americans: 90% or so of the latter died of old world diseases. Perhaps one thing is the size of the Eurasian continent: more pests and diseases evolved, and the trees developed resistance to wider selection of diseases.

Does this sound logical to you?

- Kouta

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James Parton
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Re: GSMNP on alert for Emerald Ash Borer.

Post by James Parton » Mon Aug 23, 2010 10:02 am

Kouta,

Will is far more knowledgeable on these questions than I but concerning the chestnut blight, to the best of my knowledge it was a serious threat to the European Chestnut trees there but research on hypovirulence saved them. The study of viruses that attack the fungus has not been near as successful here. They believe the fungus has more variation here and therefore more resistance to the virus. Castanea Sativa has been largely saved in Europe while the related Castanea Dentata has been nearly destroyed in the US. The European species is only slightly more blight resistant but that probably would make little difference by itself.

James
James E Parton
Ovate Course Graduate - Druid Student
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New Order of Druids

http://www.druidcircle.org/nod/index.ph ... Itemid=145

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KoutaR
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Re: GSMNP on alert for Emerald Ash Borer.

Post by KoutaR » Mon Aug 23, 2010 11:39 am

James, I did not know that hypovirulence thing. Thanks!

Kouta

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James Parton
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Re: GSMNP on alert for Emerald Ash Borer.

Post by James Parton » Mon Aug 23, 2010 11:55 am

Kouta,

According to this link much of the spread of the fungal virus in Europe was of natural origin. I have read somewhere else that some of Europe's more significant chestnut trees have been or where inoculated with the virus. Natural hypovirulence did not save the chestnuts here and inoculating trees has had only limited success. It seems that on trees in which the virus works, that the virus or virus infected fungi do not spread well enough to infect/protect other trees. They also seem to be more strains of the fungus here reducing the viruses ability to destroy them.

http://www.uoguelph.ca/~chestnut/hypovirulence.htm

Now if only a virus could be found to kill EAB or HWA.

James
James E Parton
Ovate Course Graduate - Druid Student
Bardic Mentor
New Order of Druids

http://www.druidcircle.org/nod/index.ph ... Itemid=145

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KoutaR
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Re: GSMNP on alert for Emerald Ash Borer.

Post by KoutaR » Mon Aug 23, 2010 12:08 pm

James Parton wrote:Now if only a virus could be found to kill EAB or HWA.
Yeah. Though there is always possibility that such a virus would be fatal to North American native insects relative to EAB/HWA.

Kouta

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