A Note of Caution when using DDVP strips for Pest Control
The recent news coverage and re-emergence of bed bugs has made people more aware of the potential to host these pests and others in their homes. In response, more people have been using slow release pesticides for controlling these pests and others (such as cockroaches, spiders, and silverfish to name a few). If not carefully used, the active ingredient DDVP or dichlorvos can cause significant illness to humans as noted by a CDC report on pest-strips. Dichlorvos is the active ingredient in the products such as Nuvan and Prostrips, but is also active in other products used as pesticides. Carefully inspect the label of any product you use and be sure to follow safe handling procedures to avoid unnecessary risk.
A recent blog post by Mike Merchant, PhD discusses these findings:
For anyone unfamiliar, dichlorvos is the active ingredient in (among other products) Nuvan™ Prostrips™, a slow release pesticide formulation for control of bed bugs, "flies, gnats, mosquitoes, moths, silverfish, cockroaches, spiders, beetles, earwigs and other pests". Dichlorvos looked like it might have seen the last of its days a few years back, at least partly because of its acute toxicity. It is a holdover from the era of organophosphate insecticides, and like all OPs, it acts as an acetylcholinesterase inhibitor. But dichlorvos has a unique property: its relatively high volatility makes it useful as a fumigant. And thanks to its effectiveness against bed bugs, dichlorvos now appears to be staging a comeback.
Dichlorvos kills pyrethroid-resistant bed bugs. But it can also hurt people if not used carefully as described in the label. The CDC study reports on 31 acute DDVP pest strip–related illness cases recorded from seven U.S. states and Canada from 2000 to 2013 (more cases undoubtedly occurred that were not part of this study). Most of the illnesses resulted from using the product in commonly occupied living areas (e.g., kitchens and bedrooms), in violation of label directions. According to the report, "Although 26 of the 31 cases involved mild health effects of short duration, five persons had moderate health effects." Illnesses included neurological, respiratory and gastrointestinal symptoms. Effects due to dichlorvos overexposure usually resolve themselves completely, according to the study; but make no mistake--this insecticide should be used with care.
Not only is it important for individuals to read and understand the directions ,but it is also important for industry professionals to carefully read and understand applications.
Some key label points Dr. Merchant emphasizes about Nuvan™ and similar strips are:
- Do not over-apply. One 16 gm strip is sufficient for treating 100 to 200 cubic feet. Having said that, do your technicians know how to estimate cubic feet? A typical 6' by 12' by 8' walk-in closet is approximately 575 cubic feet (a simple multiplication of length x width x height) and would require 3 to 5 strips--6 would be an over-application.
- Around the home, strips may only be used in closets, wardrobes and cupboards, storage units, garages, attics or crawl spaces. Other sites outside the house are also listed on the label.
- Do not use in kitchens or food prep or storage areas where unwrapped food may be exposed. Kitchen utensils should not contact the strips.
- Pets and children should not play or sleep where strips are in use, nor should the strips be used in any room where humans are likely to spend more than four hours a day. An important sidenote here: most of the illnesses (65%) reported in the CDC paper occurred when exposures exceeded four hours per day.
If you need additional information about handing pesticides safely, you can find information on handling and container disposal.