Rats vs rats
Jane McGary (Fri, 03 Sep 2004 19:55:03 PDT)

Arnold wrote,
I have heard that there are some rodenticides that don't allow secondary
poisoning such as was described in the death of the borzoi. I think it
may be zinc phosphide that reacts with the acid in the gastrointestinal
tract and releases a gas that poisons the rodent. The gas does its thing
and then moves on and secondary poisoning is not a problem. Of

Zinc phosphide was one rodenticide mentioned by the state agent I
consulted. It is not used in bait, as far as I could tell -- it is applied
to the soil underneath a sheet of plastic, and poisons the rodents
directly. It can be obtained in Oregon only by people who have state
pesticide applicator's licenses.

The poisoned grain I have heard mentioned was said to be treated with
strychnine. This does cause secondary poisoning. I thought it likely that
the voles would die underground in their tunnels and not be available to
scavengers, but I don't have any of this poison, anyway, and am unlikely to
use it. There MUST be something appropriate to use, though. I've lost very
rare and valuable bulbs at times.

The feral cats frequent the bulb frames and surely deter some rodent
activity there, although their leavings are disgusting. I don't keep
domestic cats because I disapprove of their predation on wild birds.

Jane McGary
Northwestern Oregon, USA
Northwestern