The Silent Spring Revisited by Bill hayes(April 2013)

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In 1962, author Rachel Carson wrote a series of articles that warned the public of the dangers of using common garden and household chemicals. Her arguments are still debated today and like any point of view, there are two sides to be considered. The point of today’s column is not to choose a side but to stress the safety issues when using a chemical approach to solve a garden problem.

Ms. Carson, through a series of articles published by the New Yorker magazine, warned of the overuse of DDT to control insects, mainly mosquitos. She also included other pesticides that, in her opinion, contributed to the death of fish, domestic animals and even humans. The counter argument from chemical companies and government agencies was that the proper use of these chemicals prevented the spread of dangerous diseases including malaria. Both arguments had merit and both parties used slanted information and statistics to prove their point.

Today’s column is to serve as a reminder that our homes contain sufficient chemicals to cause great harm to children and pets along with the adult homeowner. Our kitchens, bathrooms, basements and garages contain a wide variety of products that do marvelous things when used properly. They can also be extremely dangerous when over used or mixed improperly. With a little common sense we can continue to control the insects and diseases that attack our trees, ornamentals and lawns without a concern for harming the environment. The problem, is that we rarely monitor our chemical supplies and that can present a potential dangerous reaction.

Consider the recent explosion in West, Texas where a fertilizer plant exploded killing 14 and injuring 200. The plant produced ammonium nitrate, a common fertilizer high in nitrogen used in agriculture and home lawns. This plant had hundreds of tons of this product along with anhydrous ammonia that was the base material for producing it. As a stand-alone product, ammonium nitrate is benign. A fifty pound bag of nitrogen fertilizer in the garage would normally, not be considered a threat. But, in combination with other common materials it can cause a dangerous reaction. Many of these other benign chemicals can be found in most garages.

A good weekend project would be a thorough inventory of your garden chemicals. This would include opened bags of granular fertilizer, insecticides, herbicides and fungicides. Air and moisture exposure combine to solidify granules and reduce their effectiveness. If they have been opened for more than six months, get rid of them. Now take a look at the number of liquids stored in glass or plastic containers. How long have you had them? Some of these products have relatively short shelf lives when kept sealed. If left open, they could be ineffective after a few months. Because of the tremendous number of products sold for home use it would be impossible to give the shelf lives of each product in a short column. The Internet has information on all of the common chemicals found in your garage or storage area. A simple Google search will give you an answer. Most sealed chemicals will be effective for a couple of years while some will last much longer. Exposure to heat and air will reduce the storage life and render the products ineffective for their prescribed use. Never discard the chemicals by flushing them down a home drain of any type. If you decide to discard your old chemicals, the City of Aiken has a new service that will pick up old chemicals used for the lawn and garden. They will drop off a red container with a lid on Fridays and pick up the chemicals on your regular garbage pick-up day. The number to call for this great service is 803-642-7613.

The average homeowner uses products recommended by friends, family store owners, advertising and a host of other sources but they rarely ask if there are safety issues. Many chemicals are mixed improperly and applied improperly causing potential injury to the target plant, tree or lawn and also to animals and humans. The secret to using chemicals in a safe manner is getting the right information from a reliable source. The Clemson Extension office offers that type of service and they will research the best solution for your specific problem. Once the correct product is determined, the next step is to read the manufacturer’s label. Follow it to the letter. If it says: “one ounce per gallon”, don’t think that two will make it twice as effective. You may kill or injure the target item. Also, buy in small amounts or only as much as you intend to use for your immediate project. If you spray a liquid herbicide, do it on a calm day. Even the slightest breeze will cause chemicals to drift and harm nearby plants. We will often see herbicide damage on ornamentals that were next to an area that was sprayed for weeds. Most errors are made when we are in a hurry to finish our yard work, causing us to forget some simple safeguards.

One final note on mixing chemicals: Don’t combine two or more chemicals in a single tank. While there are some situations where this will work, there is a danger of harming the plants and yourself. There are four possibilities and the first is antagonism.  Two pesticides are applied together produce less control than when they are applied separately. In addition to reducing control, antagonistic responses also may increase phytotoxicity which causes great harm to the plant.    Enhancement is another type of interaction, but not between two pesticides.  Enhancement occurs when a pesticide is mixed with an additive to provide a greater response than if you applied the pesticide alone. A common example of enhancement is mixing an adjuvant with a pesticide. An adjuvant may be something that makes the pesticide work better. Surfactants, emulsifiers, oils or salts may help the pesticide increase its chance of success.

Synergistic responses are often confused with additive effects and occur when two pesticides provide a greater response than the added effects of each material when applied separately.  Unlike additive effects, the chemicals in a synergistic combination are not neutral toward each other.  Rather, they interact in some way that increases their effect and may increase control.  With true synergism, you can often reduce pesticide application rates without sacrificing control. 

Finally there is the possibility of mixing two chemicals that may cause a dangerous response. Some very simple household chemicals can produce violent reactions and create a dangerous condition to eyes, skin and lungs. Almost everyone has tried the simple mixing of vinegar and baking soda. A moderate acid (vinegar) mixed with a moderate base or alkaline (baking soda) can make a small volcanic type eruption and students are often amazed at the results. The average home has several common chemicals used for regular cleaning purposes that, by themselves, do an excellent job for their designed purpose. Mixing two or more of these ingredients may cause an unexpected dangerous reaction. The same is true of the garden chemicals in your garage. Don’t mix two or more unless you contact your local extension office for advice.

The Master Gardeners would like to thank the hundreds of Aiken residents that joined us at the Farmers Market last week for Spring Education Day. We hope that you enjoyed the displays and special plants that were available. We will have a similar event in the fall. The next Lunchbox Seminar will be held on May 20th at 12:30 P.M. at the Trinity United Methodist Church, 2724 Whiskey Road, Aiken, SC. Clemson Extension Service agent Vicky Bertagnolli will present “Fire Ants”. This is always a major event so plan to arrive a little early for the best seating and parking.