October 29, 2002
By Edwin Acevedo
Staff writer
Instead of using dangerous herbicides to get rid of weeds, some Central New
York schools steam them away.
Shrieking noisemakers scare off seagulls at North Syracuse's athletic stadium,
while floating scarecrows keep them out at Liverpool. Border collies might be
brought to North Syracuse to chase away Canada geese, which create a poop problem
on school fields.
And instead of putting out poison bait to catch mice, school workers now caulk
holes, store food more securely and clean regularly. Any mice that still get
into buildings eat their last meal on the end of a snapping trap.
Pests that once met a toxic end now stay away from school buildings, or they
die an environmentally friendly death. A new state law requires 48-hour notice
before use of certain restricted pesticides. Schools all over New York have
been looking for poison-free ways to rid their buildings, playgrounds and athletic
fields of pests.
The process is called Integrated Pest Management or IPM. Cornell Cooperative
Extension researchers have started a three-year study at the North Syracuse
schools to see if IPM techniques can save time and money - something every school
district wants.
The techniques focus on closing access for pests into buildings and deterring
their presence on grounds. If they do get in, regular housekeeping and secure
food storage help ensure pests don't stay.
"If you're not supplying food to mice, they're not going to hang around,"
said Joe Hammond, Liverpool's superintendent of buildings and grounds. "They're
going to go to where the food is."
Schools used to hire exterminators, Hammond said. The problem was that those
contracts typically required regular spraying, whether the buildings and grounds
needed it or not. The pesticides also left a nasty residue on curtains, desks
and floors, which schools would have to clean up.
Ants are the top nuisance in New York's schools, according to a survey conducted
last year by the state IPM program.
Keeping them away can be as simple as mopping an ant trail, which confuses them,
Hammond said. Boric acid, a non-toxic powder that becomes inert after a few
days, destroys an ant's cell structure and usually stops ant trails.
Weeds are another pesky problem. Overgrown sidewalks, fence lines and parking
lots leave a bad impression with students, staff and visitors.
Two years ago, Hammond persuaded his bosses to buy a device called an Aquacide,
which steams weeds to death. Baldwinsville, Fayetteville-Manlius and Indian
River schools each bought one a year later.
The machines cost about $11,000 to $20,000, depending on the features, said
Nick Redanty, salesman for S.V. Moffett Co. Inc. of West Henrietta, a distributor
for the machine.
Liverpool's Aquacide uses a diesel engine to heat tap water to about 260 degrees.
A small gas engine fires the steam through a gun-shaped tube tipped with four
nozzles.
Liverpool groundskeeper Paul Hoag recently demonstrated how the device works.
He waved the nozzles over a doomed morning glory that took root on the fence
line at Liverpool High's athletic stadium.
The morning glory turned shiny bright green, then became a dull, deep green.
It looked and smelled like cooked spinach. Once it dries, it will turn brown
and blow away, Hoag said.
About 100 feet away, students played football on the artificial playing surface,
where seagulls had left droppings and feathers after attacking garbage left
over from a football game. Screeching noisemakers, which make sounds like predatory
birds, work fine in North Syracuse, said Jennifer Grant, coordinator of New
York State Community IPM project through Cornell Cooperative Extension.
Hoag said Liverpool tried the noisemakers, but they bothered neighbors. The
answer was helikites, which are helium-filled mylar balloons covered in nylon,
tethered to old tires by kite string.
"They'll bob up and down, fly to and fro, spin in the wind," Hoag
said. "I think that motion helps because the birds don't like what it's
doing."
Bees are another hazard. The state law was relaxed to allow 18-ounce aerosol
cans of pesticide to be used, but mint oil also is a proven bee killer, Hammond
said.
Canada geese are becoming more of a problem, especially in North Syracuse, Grant
said. Goose droppings turned the marching band practice field into a slippery,
disgusting mess.
Border collies and similar herding dogs have successfully controlled geese in
parks and golf courses around the state, and they may show up next spring in
the North Syracuse IPM study, Grant said.
"In the spring, the time when the geese are originally nesting, is when
you want to fluster them the most and make it an inhospitable place," Grant
said. "Then, periodically bring in the dog to the site, and running them
will keep the geese away."
Grant said there is talk of teaching IPM to New York's students, modeled after
Pennsylvania's curriculum.
"This is a great way to learn science in the field," Grant said. "IPM
is required in the curriculum in Pennsylvania state schools. ... In the fourth
grade, a kid is supposed to know what IPM is as part of the testing process
... and it goes all the way up through so that in high school, you have to do
projects on IPM."
(from September 10, 2002)
Farmers exposed to pesticides have nearly a six-fold increased risk of suffering from depressive symptoms, according to a new study published in the Annals of Epidemiology (vol. 12, no. 6, pages 389-394). "Pesticide Poisoning and Depressive Symptoms Among Farm Residents" looks at exposure to individuals exposed to agriculture use of organophosphate pesticides.
Between 1992 and 1997, 761 farmers and their spouses were part of the study conducted throughout eight counties in northeastern Colorado. The study authors, Lorann Stallones and Cheryl Beseler of Colorado State University in Fort Collins, wrote that they looked at the association between pesticides and depression because higher rates of depression have been reported among farmers in some states.
Organophosphate pesticides, the most toxic family of pesticides, affects the nervous system through the inhibition of AchE, an enzyme needed for proper nervous system function. Many are easily absorbed through the skin, and are synergistic with other chemicals (meaning that the two together are more toxic than either alone), including pyrethrins and certain chemicals used in pharmaceuticals. Exposure to organophosphates have been shown to cause headache, dizziness, profuse sweating, blurred vision, nervousness, nausea, vomiting, reduced heart beat, stomach cramps, diarrhea, loss of coordination, slow and weak breathing, fever, loss of consciousness, coma, uncontrollable twitching, loss of reflexes, loss of sphincter control and chemical sensitization.
http://www.beyondpesticides.org/main.html
(posted 08/02/02)
ORLANDO, FL -- Natural killer cells are like the Marines of our immune system;
they have the capability to defend us against a lot of different threats. But
researchers have uncovered a potential counter-threat to this front-line protection.
Our body's natural killer cells could be rendered irreversibly powerless to
guard against invading tumors and viral onslaughts after only a brief exposure
to a compound found in some agricultural pesticides and fungicides.
The findings were presented at the 223rd national meeting of the American Chemical Society (ACS), the world's largest scientific society.
Triphenyltin (TPT) is a compound used in fungicides to protect pecan, potato and sugar beet crops and in pesticides to guard against Colorado potato beetles. In tests at Tennessee State University in Nashville, TN, researchers have found an apparent irreversible inhibition of natural killer cell function after as little as a one-hour exposure to TPT.
The laboratory tests were the first to ever examine TPT specifically in human natural killer cells, according to chemistry professor Margaret Whalen, Ph.D., who oversaw the work. Most other studies involved animal cell lines, she said during a telephone interview. It's also the first time the irreversible effect has been shown, she added.
The findings were presented by one of the contributing researchers, Sharnise Wilson, a chemistry major and one of Whalen's undergraduate students.
"The results indicate that brief exposures to TPT can cause persistent suppression of human immune system function," Whalen emphasized.
Although Whalen thinks that most of the TPT levels that agricultural workers are exposed to in the field are probably below what her group tested in the lab, "It's hard to know what real-life levels for phenyltins are," she noted.
In the near future, Whalen, in collaboration with Bommanna Loganathan, Ph.D., of Murray State University in Kentucky, hopes to test blood samples of agricultural workers who have been exposed to TPT to see whether significant quantities of the compound can be measured in their blood.
A type of lymphocyte cell found in the immune system, natural killer cells aggressively "fight a viral infection or destroy a cancer cell before other immune system cells recognize that they are there," Whalen pointed out. "They are quite important." A one-hour exposure to TPT "causes about a 50 percent to 60 percent loss of the tumor killing function of the natural killer cell," according to Whalen.
Even after the TPT is removed, the natural killer cells are unable to regain their strength, as evidenced by tests by Whalen's group with human leukemia cells.
"Despite the fact that the compound is no longer there, they are still unable to kill the leukemia cell," Whalen said.
Whalen believes the findings "could explain to some extent why compounds like this seem to increase cancer risks." The researchers are currently investigating whether interleukin-2 -- a protein produced by other immune system cells -- might help reverse the inhibitory effect of TPT. "It looks like it can to some extent," according to Whalen, but she quickly points out that the study is still ongoing and there is no conclusive data.
The research is primarily funded by the National Institutes of Health's Minority Biomedical Research Support (MBRS) program.
(posted 08/02/02)
Researchers report that
nepetalactone, the essential oil in catnip that gives the plant its characteristic
odor, is about ten times more effective at repelling mosquitoes than DEET --
the compound used in most commercial insect repellents.
The finding was reported today at the 222nd national meeting of the American
Chemical Society, the world's largest scientific society, by the same Iowa
State University research group that two years ago discovered that catnip also
repels cockroaches.
Entomologist Chris Peterson, Ph.D., with Joel Coats, Ph.D., chair of the university's entomology department, led the effort to test catnip's ability to repel mosquitoes. Peterson, a former post-doctoral research associate at the school, is now with the U.S. Department of Agriculture Forest Service, Wood Products Insects Research Unit, in Starkville, Miss.
While they used so-called yellow fever mosquitoes (Aedes aegypti) -- one of several species of mosquitoes found in the United States -- Peterson says catnip should work against all types of mosquitoes.
Aedes aegypti, which can carry the yellow fever virus from one host to another, is found in most parts of the United States. Yellow fever itself, however, only occurs in Africa and South America, according to the Centers for Disease Control. Vaccines and mosquito control programs have essentially wiped out the disease in the United States, although there have been isolated reports of unvaccinated travelers returning with the disease. The last reported outbreak in this country was in 1905.
Peterson put groups of 20 mosquitoes in a two-foot glass tube, half of which was treated with nepetalactone. After 10 minutes, only an average of 20 percent -- about four mosquitoes -- remained on the side of the tube treated with a high dose (1.0 percent) of the oil. In the low-dose test (0.1 percent) with nepetalactone, an average of 25 percent -- five mosquitoes -- stayed on the treated side. The same tests with DEET (diethyl-m-toluamide) resulted in approximately 40 percent to 45 percent -- eight-nine mosquitoes -- remaining on the treated side.
In the laboratory, repellency is measured on a scale ranging from +100 percent, considered highly repellent, to –100 percent, considered a strong attractant. A compound with a +100 percent repellency rating would repel all mosquitoes, while –100 percent would attract them all. A rating of zero means half of the insects would stay on the treated side and half on the untreated side. In Peterson's tests, catnip ranged from +49 percent to +59 percent at high doses, and +39 percent to +53 percent at low doses. By comparison, at the same doses, DEET's repellency was only about +10 percent in this bioassay, he notes.
Peterson says nepetalactone is about 10 times more effective than DEET because it takes about one-tenth as much nepetalactone as DEET to have the same effect. Most commercial insect repellents contain about 5 percent to 25 percent DEET. Presumably, much less catnip oil would be needed in a formulation to have the same level of repellency as a DEET-based repellent.
Why catnip repels mosquitoes is still a mystery, says Peterson. “It might simply be acting as an irritant or they don't like the smell. But nobody really knows why insect repellents work.”
No animal or human tests are yet scheduled for nepetalactone, although Peterson is hopeful that will take place in the future.
If subsequent testing shows nepetalactone is safe for people, Peterson thinks it would not be too difficult to commercialize it as an insect repellent. Extracting nepetalactone oil from catnip is fairly easily, he says. “Any high school science lab would have the equipment to distill this, and on the industrial scale it's quite easy.”
Catnip is a perennial herb belonging to the mint family and grows wild in most parts of the United States, although it also is cultivated for commercial use. Catnip is native to Europe and was introduced to this country in the late 18th century. It is primarily known for the stimulating effect it has on cats, although some people use the leaves in tea, as a meat tenderizer and even as a folk treatment for fevers, colds, cramps and migraines.
A patent application for the use of catnip compounds as insect repellents was submitted last year by the Iowa State University Research Foundation. Funding for the research was from the Iowa Agriculture Experiment Station.
Chris Peterson, Ph.D., is a former post-doctoral research associate at Iowa State University in Ames, Iowa, and is now a Research Entomologist with the U.S. Department of Agriculture Forest Service, Wood Products Insect Research Service, in Starkville, Miss.
Joel R. Coats, Ph.D., is professor of entomology and toxicology and Chair of the Department of Entomology at Iowa State University in Ames, Iowa.