Monday, April 28, 2008

Week of April 27, 2008

PA officials express concern over emerald ash borer

By Michael Pound,

The bugs are back.

Actually, the emerald ash borer, an invasive beetle that made its Pennsylvania debut last summer in Cranberry Township, hasn’t gone anywhere; in fact, officials at the state Department of Agriculture are hoping against hope that the infestation hasn’t already spread too far through the state.

As warm weather approaches, expect more discussion of the bug, the quarantine that limits movement of ash trees and products made from its wood and the statewide ban on the importation of firewood into Pennsylvania. Also, expect to see more of the surveys that located the critter along Route 19 in Cranberry last June.

The emerald ash borer — a shiny green dime-sized beetle — is a native of Asia, and probably arrived in the United States years ago after hitching a ride in wooden shipping crates. It was first discovered in this country in 2002 near Detroit, although agriculture officials there estimate it had arrived as much as 10 years prior to its discovery.

That head-start there has turned into a huge problem. The bug’s larvae — which bore through ash trees until they become adults — have killed more than 30 million ash trees in southeastern Michigan alone, and killed millions more in Ohio and Indiana.

During its normal life, an emerald ash borer doesn’t travel far on its own, but it has spread as people move ash trees products made with ash or ash firewood from infested areas. That’s why seven states — Pennsylvania, Illinois, Indiana, Maryland, Michigan, Ohio and West Virginia — all have imposed some kind of ban on the movement of ash wood products or firewood in hopes of stopping the spread.

The bug was discovered here in late June, as a team of state agriculture department surveyors moved through Cranberry Township. The state imposed a quarantine on movement of all ash wood products and all firewood from four counties — Beaver, Butler, Allegheny and Lawrence — just days after the discovery.

One month later, the state banned the importation of all hardwood firewood from outside the state. There are fines associated with violating either of the quarantines.

The infestation has the attention of Pennsylvania U.S. Sen. Bob Casey, who this week introduced legislation that would require an inventory of possible invasive species each time the United States enters into a new international trade agreement.

The Agriculture Smart Trade Act, which Casey is co-sponsoring with Sen. Debbie Stabenow of Michigan, would force the president to submit a report to Congress detailing the possible invasive species, what impact they could have if they reached the United States and plans and estimated costs for fighting an infestation.

“Increased international trade means an increased risk of importing bugs and diseases that can have devastating effects,” Casey said. “This bill will help acknowledge the risk and put in place the best safeguards so that we can prevent the accidental introduction of these harmful pests.” Full Article


New Jersey anglers, boaters warned of didymo

By Todd B. Bates,

Seen any rock snot lately? Don't laugh. This highly invasive form of freshwater algae can smother stream beds, threatening fish and other aquatic life.

And it could spread to New Jersey. State officials want anglers, boaters and other water users to block a potential rock snot invasion by cleaning boats, fishing gear and other equipment.

"We're concerned, but I don't know if we're alarmed yet," said Duane Lloyd of Brick, a member and former president of the Jersey Shore Chapter of Trout Unlimited, a nonprofit group. He wishes that rock snot had "a different name," he added.

The state Department of Environmental Protection recently issued a warning about rock snot and recommendations on how to keep it from spreading. The algae, which can form thick mats on stream bottoms, have yet to be spotted in New Jersey, according to officials and fishermen.

But New York state officials found it in the East and West Branches of the Delaware River last year and the Batten Kill in 2006, according to e-mails from Alexander J. Smith, a research scientist in the New York state Department of Environmental Conservation.

"Vermont has verified its presence in several other rivers as well," a Smith e-mail says. "The potential for spread to N.J. is very real provided there are river users that recreate in infected waters of N.Y. and then travel to N.J. waters without first following the necessary equipment cleaning procedures."

To avoid spreading rock snot to a new stream or river, people should clean all equipment such as waders, clothing, boats, fishing gear and any other object that has been in contact with the water before they go to a new site, according to the DEP Web site.

"Porous materials such as neoprene waders and felt soles used by wading anglers are prime suspects in the spread of (rock snot) among streams," according to the New York state Department of Environmental Conservation Web site.

Once rock snot affects a waterway, it can't be eliminated, according to a fact sheet by the U.S. Environmental Protection Agency and the Federation of Fly Fishers on the Web. "Infection may only need a single cell," the fact sheet says.

Rock snot is the nickname for a microscopic freshwater diatom — a type of algae — dubbed Didymosphenia geminata, or didymo for short. It is found in streams and rivers in much of North America, attaching itself to stream beds by a stalk, according to the U.S. Environmental Protection Agency Web site.

Generally drab in color, it can be light gray, brown, white or pale yellow, the DEP Web site says.

Didymo forms large mats closely resembling algae blooms or long streams that look similar to toilet paper, the Web site says. Full Article


Sudden oak death pathogen is evolving, says new study

By Sarah Yang, UC Berkeley News

BERKELEY – The pathogen responsible for Sudden Oak Death first got its grip in California's forests outside a nursery in Santa Cruz and at Mt. Tamalpais in Marin County before spreading out to eventually kill millions of oaks and tanoaks along the Pacific Coast, according to a new study led by researchers at the University of California, Berkeley. It provides, for the first time, evidence of how the epidemic unfolded in this state.

"In this paper, we actually reconstruct the Sudden Oak Death epidemic," said Matteo Garbelotto, UC Berkeley associate extension specialist and adjunct professor, and principal investigator of the study. "We point to where the disease was introduced in the wild and where it spread from those introduction points."

The study, scheduled to appear later this month in the online early edition of the journal Molecular Ecology, also shows that the pathogen is currently evolving in California, with mutant genotypes appearing as new areas are infested. These findings suggest that movement of infected plants between different regions where Sudden Oak Death is established should be minimized, said Garbelotto. Full Article


University of Florida researchers seek bugs to battle hygrophila

GAINESVILLE, Fla. — Years of hydrilla control efforts have paid off for some Florida communities — unfortunately, their success has benefited a more troublesome aquatic weed, a University of Floriday expert says.

For the past decade Hygrophila polysperma — a southern Asian plant known as “hygrophila” for short — has been taking over the ecological niche left when hydrilla was eradicated from waterways, said Jim Cuda, a UF associate professor of of entomology. It’s now a significant problem in South and Central Florida.

Like hydrilla, hygrophila (“high-GRAW-fill-uh”) was sold as an aquarium plant, got into Florida waters decades ago and survived. But the similarities end there.

Hydrilla is strictly a water weed, and can be controlled with herbicides, hungry grass carp or mechanical harvesting. Hygrophila can grow fully submerged or up on river banks. Herbicides aren’t very effective, grass carp don’t like it, and mechanical harvesting breaks its stems into tiny pieces capable of spawning new plants.

Given that scenario, Cuda and colleagues with UF's Insitutue of Food and Agricultural Sciences are looking for natural enemies that attack the plant on its home turf in India.

‘There aren’t any good, cost-effective management options for hygrophila,” Cuda said. “That’s why there’s interest in biological control.”

Last fall, Cuda and entomology graduate student Abhishek Mukherjee made a collecting trip to several Indian states, described in an article published in the spring issue of Aquatics, journal of the Florida Aquatic Plant Management Society.

The researchers found evidence of at least one insect Mukherjee hopes to capture on a return trip this summer. They also collected samples of wild hygrophila that are being genetically analyzed to determine if they’re identical to plants found in Florida.

If so, that would mean insects and diseases found in the same parts of India would be likely to attack the Florida hygrophila. If not, the researchers may keep trying to pinpoint the original home of Florida hygrophila and seek enemies there.

The UF team — which includes Cuda, Mukherjee and Bill Overholt, also a UF associate professor of entomology — recently discovered that the larvae of a native moth species will feed on hygrophila. The moth has no value as a biological control agent because it isn’t host-specific — the larvae attack more than 60 plants — and is unlikely to put a dent in hygrophila populations. But it can be a great research tool, enabling researchers to find out if hygrophila can survive defoliation, Cuda said.

In the United States, hygrophila is currently growing wild only in Florida and Texas. It’s been officially confirmed in 10 Florida counties, though Cuda suspects it’s present in at least 20. Previous research indicates the weed can survive cold climates, and could potentially spread as far as hydrilla did — from Delaware to Florida, all along the Gulf Coast, and north to Washington state. Full Article

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