GardenDesignOnline

Geraniums that Kill Japanese Beetles

Japanese beetles, the scourge of gardeners across the country, could soon be on the verge of extinction, thanks to the common ornamental geranium, Pelargonium zonale.  Researchers at the USDA's Agricultural Research Service have found that if Japanese beetles consume geranium flowers, they are paralyzed within 30 minutes, and the condition lasts for several hours.  Although the beetles eventually recover, under field conditions they usually die because predators spot them and devour them readily.

Although scientists have known for decades about the effect of geranium petals on Japanese beetles, researchers are now working to isolate the geranium compounds that paralyze the beetles ... and they're pursuing patent rights on a possible new pesticide that could be used in Japanese beetle control, which costs the ornamental plant industry nearly $500 million in damage a year.  Gardeners, of course, would far prefer a natural spray that worked to picking them off by hand!

(photo: Stephen Ausmus, USDA:ARS)

Restoration Chestnuts

American Chestnut - Castanea dentata

As most of you already know, the American Chestnut, one of our magnificent and important native trees,  was literally wiped out after a blight was imported from Asia very early in the 20th century.

Scientists have been trying for years to cross-breed remaining native trees with Asian species in order to come up with a hybrid that will look almost exactly like the old American chestnut ... but have excellent resistance to the blight.

In the winter issue of American Forests magazine, there's an article on recent chestnut research ... and it says there's now the best hope in more than a century to restore these great American trees.

You can read the full article here.

(image: USDA PLANTS Database)

Saving Hemlocks

As most of you readers already know, the wooly adelgid that attacks our native hemlock trees has been moving north at a rapid pace, threatening to wipe out the trees that remain in our Eastern forests.  Hemlocks native to western states are not affected by the beetle.

Now, two entomologists at the University of Massachusetts, Amherst, are conducting experiments with a natural adelgid predator -- the Laricobius nigrinus beetle from the Rocky Mountains --  in hopes that our remaining hemlock forests might be saved. Two years ago, researcher David Mausel began releasing the predatory beetle in hemlock study plots in Pennsylvania, New York, Maine, Massachusetts and New Hampshire.  He returns to the sites later this year to find out whether the beetles are still there and whether they've slowed the damage to hemlock trees and reduced the wooly adelgid population.

According to team member Joseph Elkinton, if they can get the beetles established in northern forests, the adelgid population may become simply "innocuous."  Elkinton says the battle to save the eastern hemlock is important because "they're one of the few evergreens whose loss affects stream temperatures, for example, so trout and other fish species are lost.  When the hardwoods move in, many characteristic birds of the hemlock forest are gone, too.  Losing the hemlock has an ecosystem-level impact."

Ash Borer Spreads to NY

The deadly emerald ash borer, which has killed millions of ash trees in the American Midwest, has now spread to New York State.

Researchers at Cornell University discovered the beetle in ash trees in southwestern New York, near Randolph in Cattaraugus County.  Specimens were sent to the USDA in Washington DC for confirmation -- and the results came back positive.

E. Richard Hoebke, a senior associate in entomology at Cornell, said the threat to the state's ash trees is extreme.  "There is the potential," he said, "for ash as we know it to be extirpated from the landscape ... and there's not a whole lot we'll be able to do about it." 

New York state has an estimated 900 million ash trees, about seven percent of the state's total number of trees.  If the beetle spreads, all of the ash trees are at risk.

It is believed that the ash borer has spread from the Midwest by the transport of infested firewood, although most states prohibit the movement of untreated firewood.  Officials plant to survey ash trees throughout New York state and begin to trap the beetles in an effort to assess the problem and come up with a strategy to combat the infestation.

(photo Kent Loeffler/ Cornell)

Air Pollution Impedes Pollination

Researchers at the University of Virginia have found that air pollution from power plants and vehicles destroys the scent of flowers, making it difficult for pollinating insects to follow fragrant aromas to their source.

The study indicates that diminishing scent trails could be a reason for declining populations of pollinators, particularly bees.   Jose Fuentes  (center in photo) professor of environmental sciences at the University of VA and co-author of the study, said that "scent molecules produced by flowers in a less polluted environment, such as in the 1800's, could travel for roughly 1000 to 1200 meters; but in today's polluted environment, downwind of major cities, they may travel only 200 to 300 meters."  Fuentes noted that this makes it very difficult for pollinators to locate flowers and the nectar they need for food.

Fuentes and his research team found that scent molecules produced by flowers are very volatile and bond with pollutants such as ozone that destroy their odors.  Therefore, the scents are chemically altered and destroyed, and when they travel on the wind, they no longer have the aroma of flowers.  The scientists believe that the pollinators are having to search longer distances to find sources of food, and perhaps are relying on sight instead of smell.

"It quickly became apparent that air pollution destroys the aroma of flowers by as much as 90 percent from periods before automobiles and heavy industry," said Fuentes.  "And the more air pollution there is in a region, the greater the destruction of flower scents."

The entire study appears online in the journal  Atmospheric Environment.

All the more reason, readers, to get on the "green" bandwagon.

Tree News

Hope for Hemlocks

Hemlocks, of course, are one of our most beautiful and versatile native trees.  There's nothing that even comes close in beauty to a hedge of Tsuga canadensis.  In recent decades, native hemlocks have been devastated by the non-native hemlock wooly adelgid, but now, researchers at Virginia Tech are studying the possibility of using a beetle from Japan that's a natural predator of the adelgid.  Scott Salom, professor of forest entomology, and colleagues have already released 17,000 beetles imported from British Colombia in 1997 and are monitoring release sites to see if the beetle is curtailing the spread of the adelgid.   They expect to release the new beetle from Japan within the next two years in similar controlled experiments.  According to Salom, these two beetles eat only the adelgid, so researchers believe they could be released in the wild without harm to other plants. Salom says there is hope that the beetle can slow the demise of the eastern hemlock.  However, he says it will probably be impossible to completely wipe out the hemlock wooly adelgid because it has been present in the country now for several decades.

And, the latest e-mail newsletter is out from American Forests, with some very newsy items:

The Oil Giant Conaco Phillips has agreed to a huge carbon reduction plan to offset its planned expansion of its oil refinery in Contra Costa county, California.  Under the agreement signed with CA Attorney General Jerry Brown, Conaco Phillips will pay $7 million into a fund for projects that will offset the 500,000 metric tons of additional carbon dioxide the plant will emit each year.  Conaco also agreed to pay $2.8 million to plant new trees in areas burned by wildfires; pay $200,000 to the Audubon Society to restore wetlands in the San Pablo Bay.

Researchers at Cornell University say pollution is responsible for about 40 percent of deaths worldwide -- another reason to plant more trees.

American Forests is getting funds from American Express to plant 100,000 trees -- part of an AE online contest.

Honeybee Update

A team of scientists working to solve the mysterious disappearance of American honeybees has found a strong correlation between the so-called "colony collapse disorder" and a pathogen called Israeli acute paralysis virus, or IAPV.

A paper on the finding was published last week in the journal Science. The team screened honeybees collected from colonies infected with the collapse disorder, or CCD, and compared them with honeybees from healthy hives.  They found the IAPV virus, which can be transmitted by the varroa mite, in all the samples from the CCD colonies.  It was the first time the virus has been identified in the United States.

Entomologist Jeffrey Pettis of the USDA's Agricultural Research Service said the research has not proved that IAPV is a cause of colony collapse disorder. "What we have found is strictly a strong correlation of the appearance of IAPV and CCD together," he said. "We have not proven a cause-and-effect connection."

Next, the scientists plan to expose healthy beehives to IAPV and find out if the collapse disorder develops. Even if it does, they believe there may be other factors that contribute to the spread of the virus.

Billions of honeybees have perished in the United States since CCD first became apparent in the winter of 2006-2007, and some beekeepers have reported losses ranging from 30 to 90 percent of their hives. Honeybees are used to pollinate more than 130 crops in the United States worth some $15 billion.  The ARS says beekeepers could face a serious problem next year in finding enough bees to pollinate their crops if no treatment can be found for CCD.

(image: ARS-USDA)

Action Plan for Bee Colony Collapse Problem

The US Department of Agriculture has announced a coordinated plan to figure out what's causing honeybee colonies to disappear.  Colony Collapse Disorder, or CCD, became widely apparent in the winter of 2006-2007, when beekeepers in many states began reporting losses of 30 to 90 percent of their hives.  Honeybees are vital to many crops across the United States. They are used to pollinate more than 130 crops and add $15 billion in crop value each year.

USDA's Under Secretary for Research, Education and Economics Gale Buchanan announced the new plan on July 13th.  "There were enough honeybees to provide pollination for U.S. agriculture this year, but beekeepers could face a serious problem next year and beyond," she said.  According to Buchanan, the new plan "provides a coordinated framework to ensure that all of the research that needs to be done is covered in order to get to the bottom of the CCD problem."

The plan says that CCD could be caused by bee pests or parasites; environmental or nutritional stress; pesticides; new or re-emerging pathogens; or a combination of those factors.  Scientists intend to survey the current situation, analyze samples for pesticides and pathogens, undertake controlled experiments to find the cause of CCD and develop plans to improve the general health bees to help them fend off future problems.

(image of healthy bees: Stephen Ausmus courtesy ARS/USDA)

Beetles Endanger Ash Trees & Baseball

Pennsylvania is the latest state that's facing the elimination of most of its ash trees.  The emerald ash borer, first discovered in Michigan in 2002, has now marched on to western Pennsylvania after decimating over 20 million ash trees in Michigan, Ohio, Indiana, Illinois, parts of Canada, and Maryland.

The destructive beetle was discovered in late June in Cranberry Township, PA, by US Dept of Agriculture surveyors during a joint federal and state effort to determine how far the beetle has spread.  A quarantine has now been imposed in Butler, Lawrence, Allegheny and Beaver countries.  It restricts the movement of ash nursery stock, green lumber, and any other ash material and the movement of any kind of firewood.  Shortly after the Pennsylvania discovery, US Agriculture Secretary Mike Johanns announced an additional $11.3 million in emergency funds for early detection programs and quarantine enforcement.

It's believed that the Asian beetles first arrived in this country in packing material from Asia, and it has no natural predators in the United States. If you see a bright green beetle on one of your ash trees, if the leaves start turning yellow before fall, or if you notice "D" shaped holes in the bark, notify your state's agricultural department or your local cooperative extension service immediately.

The emerald ash borer is also causing concern in the professional baseball world.  Eighty percent of the "Louisville Slugger" brand bats are made from ash, and most of the wood comes from Pennsylvania.  The company manufactures about 850,000 bats a year, and it supplies more than half of the bats used by major league players.  While a few top sluggers, including Barry Bonds, prefer bats made of maple, others -- including Alex Rodriguez and Derek Jeter -- always use bats made of white ash.

If the scientists can't come up with a solution to stop the beetle, a lot of batters are going to be making a switch when it comes to hitting.

(image: USDA PLANTS Database)

Colony Collapse Cure?

An entomologist at the University of West Virginia's Davis College of Agriculture believes the so-called "Colony Collapse Disorder," which has mystified beekeepers across the country, may be caused by mites. Professor James Amrine, one of top mite specialists in the United States, has been conducting research on bees since 1996.  Amrine says he is now certain that 70 percent of Colony Collapse Disorder is caused by tiny mites, which are about the size of a sesame seed, and by the pathogens they carry. 

Amrine and beekeeper Bob Noel of western Maryland have developed a three-part treatment that kills or deters mites, but it has no adverse impact on the bee colony.  The results of their research will be published June 1st in the International Journal of Acarology. The three-part remedy, using all-natural products, includes, first, treating the hives with essential oils of lemon grass and spearmint.  Amrine said that Africans have used lemon grass for thousands of years to manage honeybees. "We mix it with spearmint and it helps the bees resist the pathogens the mites carry by possibly boosting the bees' immune systems," he said.

In the second part of the treatment, a wintergreen formula is mixed with grease and placed in the hives.  According to Amrine, "it also combats pathogens and gives the honeybees an edge in improving their health. Also, the grease gets on the bees and makes it harder for the mites to try to hitch a ride."

In the third part of the treatment, pads soaked with formic acid are placed in the hive.  The pads trap heat and cause the acid to evaporate, killing over 90 percent of any mites that are present.

Colony Collapse Disorder is the latest problem to afflict American honeybees.  A recent congressional study estimated that honeybees are necessary for the pollination of $15 billion worth US agricultural products every year, including apples, nuts, soybeans, berries, alfalfa and many other crops.

For more details on Professor Amrine's honeybee research, click on the link.