Yes, it is in general a bad idea to introduce non-native species for
biological control. However, the situation is slightly different in the case
of Rumina decollata. This snail was introduced to the U.S. probably early in
the 19th century, if not before. As a matter of fact, Thomas Say described
it as a new species without realizing that Linnaeus had already described it
more than 60 years earlier. It's been recorded mainly in Florida, Texas &
California. I don't think it can survive the winters outdoors in northern
states. Helix (aspersa?) has been introduced to California. So, I suppose
Rumina could be used to control Helix populations there, but it wouldn't be
of any use elsewhere in the U.S. In my backyard in Maryland I have yet to
encounter a shelled-snail that destroys plants; introduced slugs (e.g.,
Limax maximus) do most of the damage, but I don't think Rumina would eat
slugs. But the other problem with Rumina is that when no prey is available
it eats plant material (I have been raising them solely on lettuce for 2
years now). So after they have eaten up all the Helix, they may start eating
the very plants they were supposed to protect.

The snails they are selling probably originated from the already established
populations in California. They also sell them over the Internet, but I
don't have an address.

Aydin

> -----Original Message-----
> From: Monfils, Paul [mailto:[log in to unmask]]
> Sent: Wednesday, April 26, 2000 10:30
> To: [log in to unmask]
> Subject: Using Snails for Snail Control??
>
>
> During lunch yesterday I picked up a gardening magazine
> belonging to one of
> my colleagues, and as I flipped through it I came upon a
> large full color
> picture of a snail.  I figured the attached article was about
> controlling
> snails that feed on garden plants.  And so it was - only it
> wasn't exactly
> an article, it was an advertisement - and the pictured snail
> was not one of
> the species that need to be controlled.  Rather, it was a
> carnivorous snail
> that was being offered for sale as a means of controlling
> Helix and other
> molluscan garden pests.  I visited their web site
> (www.biopest.com).  The
> snail they are selling is Rumina decollata, which they list
> as "decollate
> predatory snail".  Is this a reasonable approach to
> controlling snails in
> your garden?  Or could the importation of such a species
> result in mass
> destruction of the local molluscan fauna?
> Paul M.
>