U.S. EPA Pesticide Toxicity Classes
Most countries categorize pesticide toxicity by separating products into 3 or 4 groups. In the U.S., the Environmental Protection Agency uses the system below to indicate the environmental and human toxicity of registered products. To make these determinations, the EPA relies on several different toxicology tests conducted on mammals such as rats and mice, with the product administered orally, via inhalation, on the skin, and in the eye. The results of those tests are reported as LD50s or LC50s, which are abbreviations for "50% of the lethal dose, or 50% of the lethal concentration. The higher the LD50 or LC50 value, the safer the product is.
The decision to classify a product as Category I, II, III or IV is based on the test result that shows the highest toxicity, according to the scheme below. For more information on how the EPA categorizes pesticides, read here.
| LABEL SIGNAL WORD: | Danger | Warning | Caution | Caution* |
|---|---|---|---|---|
| TOXICITY CATEGORY: | I | II | III | IV |
| EXPLANATION: | High toxicity | Moderate toxicity | Low toxicity | Very low toxicity |
| ORAL TOXICITY LD50: | <50mg/kg | 50–500 mg/kg | 500–5000 mg/kg | >5000 mg/kg |
| INHALATION TOXICITY LC50: | <0.05mg/kg | 0.05–0.5 mg/kg | 0.5–2.0 mg/kg | >2.0 mg/kg |
| DERMAL TOXICITY LD50: | <200mg/kg | 200–2000 mg/kg | 2000–5000 mg/kg | >5000 mg/kg |
| EYE IRRITATION: | corrosive or lasting >21 days | clearing in 8–21 days | clearing in 7 days or less | minimal effects |
| SKIN IRRITATION: | corrosive | severe at 72 hrs | moderate at 72 hrs | mild or slight at 72 hrs |
*Signal word on label is not required for Category IV pesticides. Some manufacturers choose to print the CAUTION word on their Category IV products, while others do not.
A message from PACE Turf owners, Dr. Wendy Gelernter and Dr. Larry Stowell:
Sign up for the PACE Turf Information Service today, and you will have immediate access for the next 12 months to weekly emailed updates, educational videos, site-specific weather and pest forecasts, state-of-the-art web site and many other services that will help you to prevent turf problems before they occur, save you time and money, and keep you current with the newest management products and practices. At $275 per year, or just $ 0.75 per day, it's a bargain that you can't afford not to take advantage of!
For more details on member benefits, please take the tour of PACE Turf member services. Or read what other turf managers have to say about the benefits of membership. Please also feel free to contact us at any time.
Water conditioners and magic pipes: too good to be true?
Bottom line: Four different in–line water conditioning products — Aqua–PhyD, Fre–Flo, Magnawet and Zeta–Core — were tested in a four year study conducted at the New Mexico State University golf course. The research shows that none of the products tested caused any improvements in either turf quality or salinity management. The authors conclude that "After four years of research investigating several non–chemical water conditioners, a consistent positive impact of these conditioning units on turf quality and rootzone salinity could not be substantiated."
Background:
As tighter budgets and water conservation become priorities for turf managers world wide, a large number of products have been introduced that make claims ranging from improved turf quality, to reduced soil salinity to decreased water use. Unfortunately, the research needed to back up these claims is complicated, long term and expensive to produce. But now, thanks to Dr. Bernd Leinauer and colleagues at New Mexico State University, the extensive research has been done, with very conclusive results reported.
The study was performed on perennial ryegrass maintained at fairway height (5cm) at the New Mexico State University golf course. Half of the plots were irrigated with potable water (0.6 dS/m) and half with saline water (3.1 dS/m). The four test products were mounted into the water supply lines at the start of the study.
Dr. Leinauer and his team made many evaluations over the four year period, including visual turf quality, NDVI (normalized difference vegetation index) turf quality, and soil electrical conductivity, sodium concentration and sodium absorption ratio (SAR). In order to summarize the voluminous data that was produced, we identified the number of times that each test product performed in the top tier, from a statistical standpoint. We were hoping to see some products that performed better than the non–treated check plots, but this was sadly not the case, as shown below:
Summary of 2006 – 2008 data on turf quality and salinity management (soil sodium and SAR values). Of the 62 evaluations made during this time period, none of the test products performed better than the non treated check plots. Only data which directly compared all four test products was included in this summary.
| Type of water conditioner | Number of times in top tier | % times in top tier | |
|---|---|---|---|
| No treatment | 5 | 8.1 % | |
| Aqua-PhyD | hydro–electrical | 2 | 3.2 % |
| Fre–Flo | catalytic | 3 | 4.8 % |
| Magnawet | magnetic | 4 | 6.5 % |
| Zeta–Core | catalytic | 5 | 8.1 % |
Reference: Leinauer, B., Barrick, T., Serena, M., Schiavon, M., and Maier, B. 2012. Physical water conditioners for managing turfgrasses. Golf Course Management, November, 2012.
Demystifying soil analyses
Getting your soil reports back from the lab should be an enlightening and helpful event. But for many, the prospect of having to interpret soil test data is confusing and intimidating instead. We hope that we can help out with this problem.
The three documents below were designed to assist you in interpreting soil test data, and in using the data to make decisions about your fertility programs.
- Demystifying soil analyses
- Minimum Levels for Sustainable Nutrition (MLSN) soil guidelines
- Conventional soil guidelines
