Pesticides, medicines, and doggie sprays. (Environment).

Pesticides are considered to be very toxic materials and dangerous for humans to come in contact with, which is true to some degree. In most states, signs have to be posted in various locations on a golf course to notify golfers that pesticides have been applied because of the associated danger. What many people are unaware of is that many of the same chemicals are used in both human and animal medicine.

Most people are also unaware of how the toxicity of everyday foods compares to pesticides. The general public's perception is "pesticides" are dangerous chemicals that are applied to plants, and "medicines" are good chemicals that are given to humans or animals. In reality, often times the same chemicals that are used on plants to control pests are the same ones used on humans. The only difference is "pesticides" are perceived as bad chemicals and "medicines" are perceived as good chemicals.

Turfgrass Disease and Athlete's Foot 

In reality, it does not matter if a fungus is causing a disease on a person or a plant--you are going to have to use a fungicide to control it. The only real difference is psychological. When the turf is treated for a fungal disease, like dollar spot, the chemical used to control it, like Banner (propiconazole), is called a fungicide. On the other hand, when a person is treated for a fungal disease, like athlete's foot or yeast infections, the chemicals used like Micatin (myconazol) and Myconazole (myconazole), are called medicines.

In reality, all of these fungal diseases, whether on turf or people, are controlled by fungicides. Nail fungus is a systemic fungal disease that attacks people's toe nails. It is controlled by a fungicide called (medicine) itraconazole (sold as Sporanox). The Sporanox fungicide (medicine) must be taken internally to control nail fungus. So a triazole fungicide similar to Banner (propiconazole) that people are horrified to walk on after application to turf, think nothing of taking the fungicide orally to control nail fungus.

Perception versus reality: Banner is perceived as bad because it is applied to turf and called a pesticide, while Sporanox is perceived as good because it is put into the human body and called medicine. In reality they are both triazole fungicides.

Human and Plant Antibiotics

We have a bacterial disease of turf called bacterial wilt for which the only effective control in our research plots is the antibiotic oxytetracycline. It is not labeled for use on turf. However, oxytetracycline is labeled for use on fruit trees to control mycoplasma diseases. It and streptomycin are also used to control fire blight on mountain ash and non-baring fruit trees. Yes, these are the same two antibiotics that for years have been used to control human bacterial diseases.

Perception versus reality: When these antibiotics are applied to plants, they are considered pesticides and therefore bad. When they are taken orally or injected into the human body they are considered medicines, and therefore good. In reality, the exact same chemical that is given to humans is used on plants. You see, it doesn't matter whether the bacterium is on a plant or in a human; to control it, antibiotics (pesticides) are going to have to be used.

Insecticides and Doggie Sprays

Insecticides like carbaryl, sold as Sevin, which were used on home lawns for insect control was, for many years, also in tick and flea sprays. People who are afraid to allow their pets to go on a lawn treated with Sevin would think nothing of spraying their pet with the exact same insecticide to get rid of fleas and ticks. The general public assumes no one would ever put something as nasty as a pesticide in "doggie spray."

Today the most commonly used flea control product is imidacloprid, sold as Advantage Flea Control. This is the same active ingredient that is in the insecticide Merit, the most widely used insecticide for the control of grubs on golf courses and home lawns. People who are afraid to let the pets out after an application of Merit think nothing of placing droplets of the same insecticide on the dog or cat's neck to control fleas.

Perception versus reality: The insecticides carbaryl and imidacloprid are considered bad when they are applied to turf, prompting people to ask questions like, "Is it safe to let my pet on the treated lawn?" However, they will use the exact same insecticide to rid their pets of fleas, totally unaware that the chemical that went on the lawn is in the flea control product.

Shrubs and Head and Body Lice 

Head and body lice are primarily treated with pyrethroid miticides. These are the same class of chemicals used to control mites on shrubs. While people are horrified to be near someone spraying the shrubs around the house with a pyrethroid miticide, they would think nothing of applying a pyrethroid miticide to themselves or their children to rid them of head or body lice. These pyrethroid pesticides are also used in household sprays to treat furniture or carpeting to rid them of fleas or ticks. So people who are afraid when someone sprays their shrubs outdoors with a pyrethroid pesticide think nothing of spraying the same pyrethroid pesticides in an enclosed environment, because they presume it is a "carpet cleaner" and not a pesticide.

Perception versus reality: It seems pesticides are only bad when they are applied to plants; applying them to people, animals, or carpeting is just fine.

Application Rates

The older pesticides used on golf courses are applied at approximately one pound of a.i. (active ingredient) per acre. That is 16 ounces per acre, or 0.4 ounces per 1,000 square feet. So an average 5,000-square-foot green would receive two ounces of a.i. of the pesticide. The newer reduced risk pesticides are applied at approximately one-eighth of a pound a.i. per acre. This is two ounces of ai per acre, or .05 oz. per 1,000 sq. ft. So an average 5,000-sq.-ft. green would receive 0.2 oz. of a.i. per green. There is obviously not a lot of material being applied to the environment.

Fungicides are used more than any other pesticides on golf courses requiring repeated applications throughout the season. Table one shows the LD50 of the various fungicides and how they relate to everyday products. An LD50 is the rate at which 50 percent of the test animal population (normally rats) dies after ingestion of the substance. It is based on mg of the substance per kg of body weight. The lower the LD50 value, the more toxic the substance.

Editor's Note: This article is based on a presentation made at the 2003 CMAA Conference. His remarks offer insight for managers facing communication issues regarding the use of pesticides at their clubs.

Caffeine            250
Subdue Maxx         669
Aspirin             780
Koban              1070
Bayleton           1470
Banner             1517
Eagle              1600
PCNB               1700
Banol              2000
Signature          2000
Rubigan            2500
Salt               3320
Chipco 26GT        3500
Ethyl Alcohol      3800
Fore               4500
Hertiage           5000
Clearys 3336       7500
Daconil Ultrex   10,000
Prostar          10,000
Vorian           10,000

J. M. Vargas Jr.

Professor, Dept. of Plant

Pathology

Michigan State University