Research Results

Better Mosquito, Tick Repellents in the Wind?

Judy McBride, ARS News Service, USDA, (301) 504-1628, jmcbride@ars.usda.gov

Slap, slap . . . scratch, scratch. It's a familiar aggravation for billions of people who live with mosquitos. But effective repellents to keep those pests from biting--and possibly transmitting serious diseases--have been few and far between. Now, the Agricultural Research Service is seeking a patent on a method for selecting the most effective version of a repellent discovered by ARS researchers more than 20 years ago.

Using the method, ARS entomologist Jerome Klun recently identified one version that is three to four times more effective at preventing yellow-fever-transmitting mosquitos from biting than the original repellent. It's also the optimal version against the species that transmits West Nile virus. The original repellent, called 220 for short, is based on piperidine, a hexagonally-shaped molecule found in trace amounts in black pepper. Two other chemical groups are attached to this hexagon, but each can attach at two different angles. So the repellent can appear in four different versions, known as optical isomers, that can be identified by the way they bend light rays. The number of potential repellents is not limited to these four optical isomers. Other chemical groups can attach to the piperidine scaffold at various locations and angles, yielding dozens of candidates for testing, according to Klun, at ARS Chemicals Affecting Insect Behavior Laboratory in Beltsville, Md. http://www.barc.usda.gov/psi/caib.

Unlike DEET—the principal mosquito repellent for half a century--piperidine-based repellents don't dissolve plastics, such as sunglass lenses or auto paint. And early reports from an interested company suggest they easily formulate into creams. The original piperidine-based repellent has undergone toxicological testing in a U.S. Army laboratory and passed muster for experimental use on people. Products intended for commercial sale in the United States would have to undergo additional toxicological testing required by the Environmental Protection Agency.

Clean Sweep 2001: Dishing the Dirt on Nationwide Pesticide Disposal

Nancy Fitz and Jude Andreasen, Office of Pesticide Programs, The U.S. Environmental Protection Agency (EPA), fitz.nancy@epa.gov, (703) 305-7385 or andreasen.jude@epa.gov, (703) 308-9342.or at the website http://www.epa.gov/pesticides
Source: http://aenews.wsu.edu/Mar02AENews/Mar02AENews.htm#CleanSweep

This report summarizes of state and local government efforts to protect the environment by collecting and disposing of unwanted agricultural pesticides. Over the past twenty years, state and local governments have collected and safely disposed of more than 24.6 million pounds of unwanted pesticides. These efforts, known as "Clean Sweep programs," focus on agricultural pesticides but may also include other pesticides, such as those used by homeowners, golf courses, or highway departments along their rights-of-way. There is no federal mandate to conduct these collections.

Clean Sweeps are the results of state and local initiatives. The states have adopted a variety of approaches to finance and implement their programs. While some programs are conducted on the county level, the Clean Sweep Report classifies the information by state. All of the programs have the same goal: fostering environmental protection and pollution prevention by removing these potentially hazardous materials from the environment.

Forty-six states have conducted at least one Clean Sweep program. The number of states participating in Clean Sweep activities increased rapidly from the late 1980s to the middle 1990s.

Based on data provided by the states, EPA estimates that Clean Sweep programs nationwide collected over 24.6 million pounds of unwanted pesticides from 1980 through 2000. A relatively small amount of pesticide was collected through 1991 – about 2.0 million pounds. The annual total averaged almost 2.9 million pounds between 1995 and 2000.

In nearly seventy-five percent of the states with Clean Sweep programs, the state’s Department of Agriculture or the pesticide regulatory agency has the lead for organizing and overseeing the program. Twenty-five states use single-day events as their only collection method, but other states use combinations of single-day events, permanent sites, and on-site pick up. Most collected material is incinerated as hazardous waste. Based on data from fifteen states, the cost per pound to dispose of unwanted pesticides has decreased significantly over the past decade. However, the cost of Clean Sweep programs is minor compared to the cost of cleaning up the pollution that can result from improper disposal of unwanted pesticides. The quantity of unwanted pesticides collected and disposed by Clean Sweep programs is only a tiny fraction of the pesticides used in the United States.