In Ft. Collins we've had several sprays re: West Nile with permethrin-based products.
I didn't get the basil and parsley covered. What should I do to clean it to be able to use it in foods?
Larimer County Colorado
Permethrin is sold in many products for control of insects on vegetables and herbs. Most labels indicate that, when applied using all label instructions, that it can be safely applied up to the day of harvest (when sprayed on the plants). When applied as a dust, most labels suggest a waiting period of 1-3 days before harvest. These instructions would be for sprays directly made by the gardener to the plants in the garden. Drift from mosquito spraying would be expected to be of much lesser concentration, so any potential hazard would be much less than if the plants in the garden were being sprayed directly by the gardener.
If you are certain that the product applied was permethrin, there should be no concerns. If you do have any concerns, rinsing the harvested material well with water should suffice. That said, if you have any concerns beyond what I have said here, you could choose to not harvest and consume the herbs.
Without suggesting that you should or should not consume these herbs, the research with permethrin along with its year's of use would indicate that the herbs would be safe to harvest and consume.
Thanks, and let me know if you have any other questions,