kinda thought CS would not be in any answer, sorry Mike, but i KNEW this great list would come up with the answers. i like this best:
"This suggests that a regular spray of leftover coffee, which tends to have a caffeine content of about 0.1 to 0.05 percent, might control nighttime crop losses in the garden. " Lagoon ----- Original Message ----- From: "Dan Nave" <dn...@mn.nilfisk-advance.com> To: <silver-list@eskimo.com> Sent: Monday, July 18, 2005 10:37 AM Subject: CS> > http://www.sciencenews.org/articles/20020629/food.asp > > Slugging It Out with Caffeine > Janet Raloff > > Anyone who has raised tomatoes in a moist environment knows the > tell-tale sign: Overnight, a ripe, juicy orb sustains a huge, oozing > wound. If you arrive early, you might catch the dastardly culprit: a > slug. > > > In one test, scientists sprayed soil with dilute caffeine and then > watched as slugs, like this one, made haste to get away. > Hollingsworth/ARS > > > Who would have thought that a defense was as close as your coffee cup? > > > Federal scientists have discovered that the same chemical that provides > the pick-me-up in a cup of java is a deadly turn-off to snails and > slugs. Caffeine renders their food unpalatable. Applied to their soil, > the stimulant causes snails and slugs to writhe uncontrollably. At the > proper dose, these mollusks succumb to the neurotoxin fairly quickly. > > The discovery emerged in greenhouse experiments by Agricultural > Research Service scientists in Hilo, Hawaii. As the wettest city in the > United States, it's slug heaven, observes Robert G. Hollingsworth, who > led a series of caffeine experiments reported in the June 27 Nature. For > each trial, he mined 50 to 100 slugs from the field*aka his backyard. > > > But why caffeine? Earl Campbell, now with the U.S. Fish and Wildlife > Service, and his ARS colleagues stumbled on this anti-slug measure while > looking for a pesticide to eradicate noisy frogs. > > Because there are frogs > > The Hawaiian Islands evolved in the absence of amphibians and reptiles. > However, some 40 different species of these nonnatives have taken up > permanent residency on at least a few of the state's lush islands. They > arrived through trade, stops by tourist vessels, and the deliberate > release of pets. > > Two of the more recent and troublesome of these aliens are tiny > Caribbean frogs from the same genus. Though both are noisy, the species > Eleutherodactylus coqui has become especially vexing. Its mating calls, > which can go on all night*and year-round in low-lying areas*reach 90 > decibels, the volume of barking dogs and vacuum cleaners. The > Occupational Safety and Health Administration requires that workers wear > hearing protectors when noise averages 85 decibels or higher. At that > volume, sustained exposures can produce irreversible hearing loss. > > In parts of Hawaii since the mid 1980s, this volume has become typical > of backyard coqui choruses. So, while amphibian populations throughout > much of the world are declining or becoming extinct, mushrooming > populations of Hawaii's frogs have become not only a public nuisance but > also an ecological nightmare. The situation puts state and federal > biologists charged with safeguarding Hawaii's environment in the > uncomfortable position of targeting healthy populations of cute frogs > for execution. > > After working their way through soaps, surfactants, and off-the-shelf > pesticides*all without antifrog effects*Campbell's group started to > evaluate products in the grocery store, including acetaminophen > (Tylenol) and cigarette nicotine. "We had very poor results with almost > all of these," Campbell told Science News Online. Finally, his team > tried a caffeine-rich anti-sleep preparation. "It was the only thing > that worked at a legal [label's recommended] level," Campbell says. > > When field trials established its promise, the researchers petitioned > the Environmental Protection Agency for an emergency exemption to use > caffeine against Hawaii's coqui and greenhouse (E. planirostris) frogs. > Provisional permission came through last November. Preliminary, targeted > eradication and control programs are now set to begin within the next > few months. > > It was during early evaluation of caffeine's potential that the > researchers applied a dilute concentration of the compound to the soil > in greenhouses where many frogs were holed up. At once, Campbell noticed > that slugs began surfacing and dying. > > That interested Hollingsworth, an entomologist studying pests of > ornamental plants, such as potted orchids and anthuriums. Small snails > have proven a bane to orchid growers, he notes. Though they don't hurt > the blooms, some of these shelled slugs chew away at roots, loosening > the plants' anchor. > > So, Hollingsworth launched tests of various concentrations of dilute > caffeine against those orchid snails, known as Zonitoides arboreus, and > that local garden denizen, the two-striped slug (Veronicella cubensis). > The tests showed what plants around the globe had discovered long ago: > Caffeine makes a good all-natural pesticide. > > Plants have known, all along* > > Caffeine, though associated widely with coffee, also appears naturally > in tea, cacao*the source of chocolate*and a host of other plants. > The reason, according to the 2001 opus The World of Caffeine by Bennett > A. Weinberg and Bonnie K. Bealer, flora the world over have found this > compound a useful weapon to control predation by bacteria, fungi, and > insects. > > However, the book notes, exploitation of this natural poison comes at a > price, because "the very drug that helps them destroy their enemies > ultimately kills them as well." With coffee, for instance, as branches, > leaves, and berries fall to the ground, caffeine leaches out of this > litter, eventually enriching soil caffeine concentrations to a point > where they become toxic to the parent plant. This is one reason that the > productivity of coffee plantations tends to wane with time, the book > observes. > > In their new field trials, the Hawaiian scientists have also seen > evidence of plant toxicity with some of the higher pesticidal > concentrations of caffeine. However, they've also witnessed responses of > the targeted pests to low concentrations. > > A 4-ounce solution of 2 percent caffeine applied to the soil of 4-inch > greenhouse pots devastated garden slugs, Hollingsworth found. Within 3.5 > hours, 75 percent of the slugs emerged from hiding in the soil. Within 2 > days, 92 percent of the slugs were dead. When the researchers dropped > the concentration of caffeine by half, it took another day to achieve > the same body count. When they halved the caffeine level yet again, the > kill rate dropped to 55 percent and the time to death extended to 5 > days. > > Even concentrations of only 0.1 percent caffeine may prove useful. > Sprayed onto such slug-prized cuisine as cabbage leaves, those > concentrations deterred feeding by 62 percent, respectively, when > compared to uncaffeinated salad greens. This suggests that a regular > spray of leftover coffee, which tends to have a caffeine content of > about 0.1 to 0.05 percent, might control nighttime crop losses in the > garden. > > Hollingsworth also reports a "contact" repellency of caffeine on garden > slugs. In one unpublished experiment, he sprayed half of the soil in a > pot with 2 percent caffeine and left the rest untreated. "I put the > slugs onto the part that was not sprayed*and watched some of them go > right up to the edge of the sprayed part and then turn around," he > notes. > > Eighteen years ago, Harvard Medical School scientist James Nathanson > reported finding that caterpillars would actively avoid eating garden > leaves sprayed with caffeine. Though this led many researchers at the > time to hail caffeine as the next all-natural pesticide, commercial > pesticide manufacturers passed on any opportunity to exploit the > finding. According to Dave Ryan of EPA in Washington, the agency's > pesticide division has "no record of caffeine as an active ingredient in > any [registered] pesticide"*besides, that is, the recent temporary > permit for the use of dilute caffeine against Hawaiian frogs. > > Says Hollingsworth, "I think one reason caffeine never went anywhere as > a pesticide for bugs is that most insects have this [water repelling] > exoskeleton, making it hard for the caffeine to penetrate." Not so, > slugs and snails. "The mucus, which is the basis for their locomotion, > is very high in water content," he observes, and it permits > water-soluble caffeine easy entry. Once inside the critters, the new > Hawaiian studies show, the neurotoxic caffeine destabilizes the > mollusks' heart rate. > > Now, Hollingsworth says, the trick will be to find ways to package > caffeine so that it's available to kill frogs without posing a risk to > plants or untargeted organisms. > > For me, an avid tea drinker, I'll just try spraying vine-ripening > tomatoes with my husband's leftover coffee. It seems the best use of > that other brew. > > > References: > > Hollingsworth, R.G., et al. 2002. Caffeine as a repellent for slugs and > snails. Nature 417(June 27):915-916. Abstract available at > http://dx.doi.org/10.1038/417915a. > > Further Readings: > > Bernardo, R. 2001. EPA approves plan to fight frogs with caffeine. > Honolulu Star-Bulletin (Oct. 2). Available at > http://starbulletin.com/2001/10/02/news/story3.html > > Hawaii Department of Agriculture (HDOA) pesticide label (and > attachments) for application of caffeine to control Caribbean frogs > (Eleutherodactylus coqui and Eleutherodactylus planirostris) in the > State of Hawaii: Label. > > Milius, S. 2000. Colossal study shows amphibian woes. Science News > 157(April 15):247. Available at > http://www.sciencenews.org/20000415/fob8.asp. > > Raloff, J. 2000. The power of caffeine and pale tea. Science News > 157(April 15):251. > > _____. 1984. Caffeine: The 'all natural' pesticide. Science News > 126(Oct. 13):229. > > Vergano, D. 1996. Smallest frog leaps into the limelight. Science News > 150(Dec. 7):357. > > Weinberg, B.A., and B.K. Bealer. 2001. The World of Caffeine: The > Science and Culture of the World's Most Popular Drug. New York: > Routledge. See > http://reference.routledge-ny.com/books.cfm?isbn=0415927226. > > > Sources: > > Earl Campbell > U.S. Fish and Wildlife Service > Box 50088 > Honolulu, HI 96850 > > Robert G. Hollingsworth > U.S. Pacific Basin Agricultural Research Center > USDA-Agricultural Research Service > PO Box 4459 > Hilo, HI 96720 > E-mail: > > Dave Ryan > Press Office > Environmental Protection Agency > 1200 Pennsylvania Avenue, N.W. > Washington, DC 20460 > > > > > > > -- > The Silver List is a moderated forum for discussing Colloidal Silver. > > Instructions for unsubscribing are posted at: http://silverlist.org > > To post, address your message to: silver-list@eskimo.com > Silver List archive: http://escribe.com/health/thesilverlist/index.html > > Address Off-Topic messages to: silver-off-topic-l...@eskimo.com > OT Archive: http://escribe.com/health/silverofftopiclist/index.html > > List maintainer: Mike Devour <mdev...@eskimo.com> > > > -- > No virus found in this incoming message. > Checked by AVG Anti-Virus. > Version: 7.0.323 / Virus Database: 267.9.0/50 - Release Date: 7/16/2005 > >
