Herb Garden and Pesticides
Answered by: Conrad Richter
Question from: Cathy Cole
Posted on: July 4, 2001

I have an extensive herb garden in my yard, mostly creeping thyme, lemon marigold and geraniums of various scents and flavors. We have a large infestation of ants in our community and have a bi-monthly extermination service – used largely before we planted our herb garden. My concern is over the use of Talstar (Bifenthrin) which the company says is not systemic to the herb and can still be eaten. I wished to supervise the spraying of my property, but unfortunately that did not happen. Now I am concerned re: the safety of my plants for consumption by either us or the animals that wander into the yard.

Do you have any information re: this chemical and any advice you can share?

We are not familiar with this chemical. It belongs to the pyrethroid family of chemicals which gets its inspiration from the natural insecticide derived from the pyrethrum flower. It is man-made.

The material safety data sheet (MSDS) and label information is available from the manufacturer’s website (http://www.fmc-apgspec.com/labels.htm). The product labels for the various bifenthrin products sold by FMC indicate that these products are not approved for use on edible plants in the.

The manufacturer claims that the bifenthrin molecule has residual action which suggests that it persists in the garden. Here is what the MSDS says:

"ENVIRONMENTAL DATA: In soil, bifenthrin is stable over a wide pH range and degrades at a slow rate which is governed by soil characteristics. Bifenthrin will also persist in aquatic sediments. Bifenthrin has a high Log Pow (>6.0), a high affinity for organic matter, and is not mobile in soil. Therefore, there is little potential for movement into ground water. There is the potential for bifenthrin to bioconcentrate (BCF = 11, 750)."

The MSDS goes on to say that bifenthrin is highly toxic to fish and aquatic arthropods, but only slightly toxic to birds and mammals.

I would be concerned about exposure to this chemical, both during application and residual contact. You may wish to contact the manufacturer for more information.

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