Has anyone used permethrin on their grape vines? I was told the EPA has
not approved it's use on grapes or any other small fruit such as
blueberries and cherry tomatoes. Wonder why?

gwtx2 wrote:
Has anyone used permethrin on their grape vines? I was told the EPA has
not approved it's use on grapes or any other small fruit such as
blueberries and cherry tomatoes. Wonder why?

Here is link to a permethrin residue study:
http://www.inchem.org/documents/jmpr...no/v82pr27.htm

My guess why EPA has not approved use on small fruit is that the high
surface area per pound on small fruits means higher residue levels than
on larger fruit... and residue levels are what is trying to be
controlled. Also, most people don't rinse their grapes prior to
fermenting them, so residue not rinsed off.


Here is an article which talks about the downside of use of permethrin
to control berry moth (i.e. the permethrin is also toxic to the
beneficial predaceous mites. Repeated use may result in outbreak of the
not-so-desirable European red mite.):
http://phero.net/iobc/montpellier/trimble.html

gene

gene wrote:
gwtx2 wrote:
Has anyone used permethrin on their grape vines? I was told the EPA has
not approved it's use on grapes or any other small fruit such as
blueberries and cherry tomatoes. Wonder why?

Here is link to a permethrin residue study:
http://www.inchem.org/documents/jmpr...no/v82pr27.htm

My guess why EPA has not approved use on small fruit is that the high
surface area per pound on small fruits means higher residue levels than
on larger fruit... and residue levels are what is trying to be
controlled. Also, most people don't rinse their grapes prior to
fermenting them, so residue not rinsed off.


Here is an article which talks about the downside of use of permethrin
to control berry moth (i.e. the permethrin is also toxic to the
beneficial predaceous mites. Repeated use may result in outbreak of the
not-so-desirable European red mite.):
http://phero.net/iobc/montpellier/trimble.html

gene

Thanks for the study link. I used permethrin on my grapes to control a
bad infestation of Japanese Beetles. Now that some of the grapes are
becoming ripe, I was curious to know the delta between permethrin
application and harvest. I couldn't find any data, and Bayer (the maker
of the dust I have) said that I should not eat the grapes this season
because the EPA has not approved the use of permethrin on grapes.

I have all intentions of washing the fruit in soapy water, but I was
not sure why the EPA had approved carbaryl (Sevin) and not permethrin.
From the study, it appears carbaryl brings down quicker than
permethrin.

I also found an interested comment in this document:
http://www.ipm.msu.edu/pdf/FQPATarge...idueReport.PDF

"Washing the samples did not decrease the amount of permethrin detected
(Table 3)."

I'm not understanding why washing does not remove permethrin from
grapes, but it does for other fruits and vegetables. Does the grape
absorb or bond to this particular pesticide?

Anyhow, To be on the safe side, I may have to throw away the grapes
this year, and next year I'll use something less toxic, like
insecticidal soap or just let the beetles have their way. A lesson
learned.