Oriental Chestnut Gall Wasp Ohio--An Update
by Bob Stehli
In June of 2003 an isolated infestation of Asian Chestnut Gall Wasp (Dryocosmos kuriphihus) was discovered in Broadview Heights, Ohio. (See
nutnews.htm#article9 for background.) At that time the infestation seemed to be confined to four mature trees within one half mile of each other. There were old galls possibly up to two years old on one of the trees.
The Ohio Department of Agriculture who was alerted to the presence of the pest in June, took action late in the fall, and sent out a request to the three property owners that they destroy the trees at their own expense. Unfortunately the wasps had long since emerged and moved on. Incidentally, one owner did comply (poor devil).
Since 2003 I have searched diligently at my Mantua and Hiram chestnut orchard for galls. I found galls in my Hiram orchard for the first time in June of 2005. The Hiram orchard consists of about 800 trees and is located about thirty-five miles southeast of Broadview Heights. Six trees had galls. As I was removing the galls from the most affected tree, I found four old galls from the summer of 2004, showing that the pest had actually arrived in the orchard in the summer of 2003. I removed all the galls I could find and sent them, with Rodney Cooper, to the Plant Entomology Department at the University of Kentucky where he and Dr. Lynne Rieske-Kinney are studying the intersection of Asian Gall Wasp and its predators (financed in part by an NNGA grant).
To my surprise, Dr. Rieske-Kinney and Rodney Cooper have found the Asian Chestnut Gall Wasps at Broadview Heights as well as my Hiram orchard are already being parsitized by Torymus sinensis, a tiny parasitic wasp which is believed to be responsible for the precipitous decline in Gall Wasp in the southeastern United States. Oh Happy day!
My brother, who owns one of the infested trees in Broadview Heights, informed me that there was a noticeable decline in the number of galls in his tree this summer (2005).
Last fall, I found galls in one tree in my Mantua orchard, which is about thirty miles southeast of Broadview Heights.
I expect from the number of galls I saw this summer that my two orchards will be moderately infested this summer (2006) and I would guess that Pennsylvania will be seeing a few gall wasps along their western border. Hopefully the same factors that kept the Chestnut Blight from Michigan will slow the gall wasps' approach as well.
With Asian Gall Wasp now occupying much of the eastern chestnut range, I would advise anyone who is purchasing chestnut trees or securing scion wood from outside sources to be very watchful of the new growth on them. If you see any galls (about one half of an inch in diameter on new stem appearing in late May and June), simply remove the galls and burn them--immediately, if possible. You might save yourself from (or at least delay) and introduction of the Asian Chestnut Gall Wasp.
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Sudden Oak Death Syndrome Spreads to Douglas Fir and California Redwoods
Researchers do not know the long-term impact the disease will have on Douglas firs and California redwoods, but both will be added to the official list of susceptible species, making them subject to state and federal quarantine regulations. Quarantined regions include now include 12 counties in California and 9 square miles in Oregon.
The Douglas fir is a major timber and Christmas tree species; the redwood is used as timber, and its bark, for landscaping. The continued spread of this disease could have a major economic impact since the harvest of Douglas firs are worth more than a billion dollars a year in the US.
Researchers found infected Douglas fir and redwood in the wild a few months ago. Recently completed tests have shown that healthy seedlings and saplings could be infected in the laboratory with the disease. However, researchers still do no know whether large mature Douglas firs and redwood trees can be infected or killed by the disease. Symptoms experienced by infected trees vary by species and range from death in oaks to spots on leaves in bay trees. It remains to be seen how Douglas firs and redwoods will react to infection. So far researchers found that the disease killed the growing branch tips of infected Douglas fir saplings. It killed young sprouts at the base of infected redwoods and the needles of the tree.
There is no known cure for this disease. Experiments are being conducted to find preventives that can be applied to a forest. Chemical sprays have been successfully used in Austrailia where a relative of sudden oak death has destroyed vast forests. However, sprays would not be feasible in heavily populated areas.
For the history and symptoms of Sudden Oak Death Syndrome, click here.
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Want to Lower Your Cholesterol? Eat Walnuts!
Doctors usually advise patients with high cholesterol to eat a Mediterranean diet, which is low in animal fats, high in fruits, vegetables and olive oil (monounsaturated fat). Recent studies show that adding walnuts to your diet may reduce cholesterol levels further. Studies show that walnut extracts, called polyphenolic compounds, prevent the oxidation of cholesterol. Oxidized cholesterol contributes to plaques that cause heart disease and strokes.
A study from Spain compared two diets--one a normal Mediterranean diet, another the same diet, but with walnuts substituted for some of the olive oil and other high fat foods. The diet included 11 walnuts a day, replacing 35% of the fat calories as compared to the normal Mediterranean diet, for six weeks. The participants in this study were 55 men and women, average age 56, who were being treated for high cholesterol. At the end of the study, the walnut group had significantly lower total cholesterol as well as lower low-density lipoprotein levels (LDL, the bad cholesterol) as compared to the regular Mediterranean diet. The researchers concluded that substituting walnuts for part of the monounsaturated fat in a cholesterol-lowering Mediterranean diet further reduced total and LDL cholesterol levels in men and women with high cholesterol.
In another study from Japan, researchers compared a diet with 12.5% of its energy from walnuts to a control diet. The walnuts were substituted for other high-fat foods like meat and fat. The results were similar to the Barcelona study. Both total cholesterol and LDL levels were significantly lower among the walnut-eaters than those in the control diet. Substituting walnuts for some of the fat in a normal diet reduces both total cholesterol and LDL levels.
The trick is to eat walnuts INSTEAD of other fats. Cutting back on other fats to compensate for the walnuts will not result in weight gain.
Journal of Nutrition, 2001, Vol. 131, No. ll, pp. 2837-2842;
Annals of Internal Medicine, 2000, Vol. 132, No. 7 pp. 538-546;
Journal of Nutrition, 2000, Vol. 132, No. 2, pp. 171-176
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Oak Disease Is On The Move
The disease that has been killing oaks in California has now been found in southwest oregon. It is thought that the disease is spread by mud and soil on car tires, boots and animal paws. The infected trees in Oregon are in a remote area, far from roads and trails. So it is not known how the trees became infected. Infected trees are now being removed to contain the spread of oak disease.
In California, the disease was found to have spread to buckeye trees. According to Matteo Garbelotto, a forest pathologist at the University of California at Berkeley, the disease seems "to have a large base of species that it can infect." Also, the disease has recently been discovered in woodlands, in an area that is dryer than coastal areas where it has thrived in the past.
According to Dr. David Rizzo of the University of California at Davis, the disease can pose a threat in the Midwest and East because northern red oaks and pin oaks, classic trees of the forests in those parts of the country, also seem susceptible.
Other scientists are also worried about the possibility that the disease can spread eastward. According to Dr. Steve Zack of Portland, Oregon, a wildlife ecologist at the Wildlife Conservation Society, "It's unprecedented to have a pathogen that's spread across so many native plant families and species so quickly. Although there are minor things called deserts and plains, and we don't know if or how the disease might spread across them, this lends no assurance to East Coast people that our problem might not also be theirs."
We'll keep you posted.
See articles below for more information on oak disease.
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Phosphonate: A Possible Cure for Oak Disease
Matteo Garbelotto, a forest pathologist at the University of California at Berkeley, discovered that phosphonate eliminated the lesions that characterize sudden oak death. (See article below for more information about this disease.) Injection was the most effective form of treatment. However, he has indicated that the findings were preliminary and that more work was needed before a specific product could be recommended. More tests are needed at different times of the year.
Phosphonate is registered as a fertilizer and, under law, it can only be used for that purpose. It could take a year of more studies before the compound is approved as a pesticide. Despite this, some have been using phosphonate to fight the disease that has been killing oaks in California.
In our last article on oak disease we reported that the pathogen that is killing oak trees was found in rhododendrons at a nursery in Santa Cruz, California and that scientists were conducting research to determine other susceptible species. Plant biologists have recently found the disease in wild huckleberry bushes in Marin County, California. The pathogen has proved highly adaptable and also has been found in rain water and in soil.
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Disease Killing Oaks In California
The fungus that has been killing tanoak trees, coast live oaks and black oaks in California has been found on rhododendrons at a nursery in Santa Cruz, California near oaks that are dying. The rhododendrons have not been dying, possibly because nursery plants are treated with chemicals. Those chemicals are being tested to see if they will work with oak trees.
In the meantime, the California Board of Forestry plans to declare a "zone of infestation" that will allow them to enter private property to control the fungus, and Oregon has put California oak products under a 90-day quarantine.
Transcontinental Link Suggested
The disease that has been killing thousands of oaks in California is caused by a strain of fungi from the genus Phytophthora that has never been seen before. University of California researchers have been told by their counterparts in Europe that rhododendron plants in Europe are also infected.
Although, there has not been an epidemic of oak deaths in Europe, there is concern that the disease can spread to oaks in those parts of Europe that are similar to California in climate.
Researchers say that a new fungus in two species in two parts of the world is unusual and suggests a transcontinental link. It is possible that the disease was spread from exported rhododendrons since people don't export oaks. It is not known if the disease started in Europe, in California, or in a third place.
Scientists are conducting research to determine other susceptible species. We will keep you posted.
If you would like to be notified of updates to this Web site, send e-mail to icomserve@aol.com with "NNGA Updates" in the subject heading of the e-mail.
Our first article written on oak disease describes its history and symptoms. Click here to transfer to this article.
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Native Chestnuts Making A Comeback
Fresh chestnuts from American-grown trees are starting to appear at farm stands and at farmer's markets, sometimes in their spiky husks. Many of these nuts are from trees that are a cross between American and Chinese trees. They tend to have most of the taste and sweetness of the American original that was wiped out by the chestnut tree blight in the early 1900's.
Still, most chestnuts sold in the US are imported from either Europe or Asia. But, if the American Chestnut Foundation is successful in its breeding program, there can be a large commercial crop of natively grown chestnuts by 2015.
Click here for continuation of article.
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NNGA Publishes "The Hazel Tree" by Cecil Farris
Cecil Farris has recounted his 35 year journey that turned him, a former Oldsmobile worker, into an authority on hazel nuts and trees.
Read about: Hazel tree culture, diseases and pests, breeding techniques, establishing backyard hazels...and more. This 74 page book contains 27 color photos and is a "must-have" for the Hazel enthusiast.
| Soft Cover |
Members |
Non-members |
| 15.00 |
19.00 |
| Hard Cover |
20.00 |
24.00 |
Add $4.00 Shipping & Handling in USA;
... . $8.00 Outside of USA |
All proceeds go to NNGA
To order, make checks payable to NNGA and send to:
The Hazel Tree,
Sandra Anagnostakis, NNGA Treasurer
P.O. Box 6216
Hamden, CT 06517
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NNGA To Fund Research Projects
Generous donations on the part of NNGA members have made it possible for NNGA to surpass its goal of $100,000 for the research fund. The fund will generate enough money for future projects.
If you are planning a project that needs funding, click here for grant guidelines.
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If you have any news to report about nuts or nut trees, contact Mr. Tucker Hill at tuckerh@epix.net.
NORTHERN NUT GROWERS ASSOCIATION, INC.
