And as Dr. Keith F. Courtenay (U.L.C., USA) has stated in his book, Colloidal Silver: the Hidden Truths :
“For all bacterial, fungal and viral attacks on plants, flowers and fruit, simply spray diluted colloidal silver on the leaves; also, add to water, mixing one tablespoon per liter.
I put silver in my hydroponic system to eradicate root rot. A friend of mine grows very rare orchids; these are sold overseas for a large amount of money. He was getting a fungus growing on some of them and they became worthless.
We came up with the idea that the silver might eradicate the fungus, as it does on humans and animals. So why not give it a try?
It worked and he is a very happy man. He has now put a spray system in and all his flowers are sprayed at regular intervals and have never had any trouble since.”
Futher from the article Silver Secrets: Another Way to Kill Pathogens.
You may have heard of colloidal silver’s healing powers in human health. Some people use it when they feel a sinus infection coming on, while others have used colloidal silver to treat skin conditions and infections, including bacteria, yeast, viruses and parasites. Known as nature’s antibiotic, it’s no surprise that colloidal silver can also offer preventative, therapeutic and restorative properties to our plants and our gardens.
Colloidal silver is essentially pure water with ultra-tiny nanoparticles of silver suspended inside. The ionic form of silver is capable of killing more than 650 different pathogens. The US Environmental Protection Agency (EPA) named silver as an oligodynamic biocide, which means it attacks primitive life forms but doesn’t harm more mature organisms.
The beauty of using colloidal silver in the garden is that it’s very safe for the plants, but it tenaciously targets the bacteria, parasites and other pathogens.
HOUSTON – (July 11, 2012) – Rice University researchers have settled a long-standing controversy over the mechanism by which silver nanoparticles, the most widely used nanomaterial in the world, kill bacteria.
Their work comes with a warning: Use enough. If you don’t kill them, you make them stronger.
Scientists have long known that silver ions, which flow from nanoparticles when oxidized, are deadly to bacteria. Silver nanoparticles are used just about everywhere, including in cosmetics, socks, food containers, detergents, sprays and a wide range of other products to stop the spread of germs.
But scientists have also suspected silver nanoparticles themselves may be toxic to bacteria, particularly the smallest of them at about 3 nanometers. Not so, according to the Rice team that reported its results this month in the American Chemical Society journal Nano Letters.
In fact, when the possibility of ionization is taken away from silver, the nanoparticles are practically benign in the presence of microbes, said Pedro Alvarez, George R. Brown Professor and chair of Rice’s Civil and Environmental Engineering Department.
“You would be surprised how often people market things without a full mechanistic understanding of their function,” said Alvarez, who studies the fate of nanoparticles in the environment and their potential toxicity, particularly to humans. “The prefix ‘nano’ can be a double-edged sword. It can help you sell a product, and in other cases it might elicit concerns about potential unintended consequences.”
He said the straightforward answer to the decade-old question is that the insoluble silver nanoparticles do not kill cells by direct contact. But soluble ions, when activated via oxidation in the vicinity of bacteria, do the job nicely.
To figure that out, the researchers had to strip the particles of their powers. “Our original expectation was that the smaller a particle is, the greater the toxicity,” said Zongming Xiu, a Rice postdoctoral researcher and lead author of the paper. Xiu set out to test nanoparticles, both commercially available and custom-synthesized from 3 to 11 nanometers, to see whether there was a correlation between size and toxicity.
“We could not get consistent results,” he said. “It was very frustrating and really weird.”
Xiu decided to test nanoparticle toxicity in an anaerobic environment – that is, sealed inside a chamber with no exposure to oxygen — to control the silver ions’ release. He found that the filtered particles were a lot less toxic to microbes than silver ions.
Working with the lab of Rice chemist Vicki Colvin, the team then synthesized silver nanoparticles inside the anaerobic chamber to eliminate any chance of oxidation. “We found the particles, even up to a concentration of 195 parts per million, were still not toxic to bacteria,” Xiu said. “But for the ionic silver, a concentration of about 15 parts per billion would kill all the bacteria present. That told us the particle is 7,665 times less toxic than the silver ions, indicating a negligible toxicity.”
“The point of that experiment,” Alvarez said, “was to show that a lot of people were obtaining data that was confounded by a release of ions, which was occurring during exposure they perhaps weren’t aware of.”