I live in a very bio diverse area of the world, which sometimes seems to be the vortex of all life forms which might bite, entangle or stab a human being, and I work with these elements daily. We have been invaded by many "non native" pests, and most of them seem to enjoy our environment, and are now trying to take it for themselves.

The local media carried a story about people reporting seeing Asian Grass Carp (a type of fish used to control vegetation, particularly hydrilla verticillata) going over the spillway at Lake Tyler East, a lake in the East Texas area.

This brings up a number of issues. Let me start by saying that no grass carp have been introduced into this lake. At least not officially. According to the parks and wildlife folks, no grass carp were allowed in the lake at this time because there is no barrier to prevent their escape. I should mention here, that these fish are sterile, and therefore pose no threat in the area of reproduction. These are the logical extensions:

1. What the people saw was another type of fish.

2. What the people saw was indeed a grass carp.

If what they saw was grass carp, I have another extension:

1.They have somehow been introduced into the waters unofficially.

At this time, I don't believe that the sighting was more than misidentification.

This however, does bring to light a potential problem in our integrated pest management programs. When we have a non native pest problem, one of the ways we handle the problem is by introducing one of the pests natural enemies to defeat it. This often works well. The question in the back of the minds of most thinking people is: Will this new species, introduced to control the other non indigenous species present it's own problems? In most cases the answer is no, at least not that we see yet. However, the question that we should be asking, is will it be a problem in the future, when we have slight environmental changes brought on by changing weather patterns or other shifts in our eco systems? There have been a number of plants brought into our country by well meaning people who were seeking to solve problems by this introduction. Jonson grass, and kudzu were both seen as being answers to a problem. Both got out of control, posing more problems than solutions. In the case of kudzu, the problems began when it was transfered from the area of introduction into the more viral Southern climates, where it has now become known in some circles as the "weed that ate the South."

Now, to the credit of most modern biologists, the new species being introduced to control the other invaders have been thoroughly researched, and are, in most cases of which I am aware, sterilized, so that the risk is kept at a minimum. This does not however, mean that mistakes are not possible, or conditions will not change in the future.

Some things you can do:

1. Don't become a part of the problem. Make sure that what you cultivate is not an invader. There are many free resources for finding out about invasive species on the internet.

2. Don't deliberately cultivate an alien pest. I have heard stories that I sincerely hope are not true of some fishing enthusiasts who have deliberately introduced hydrilla into areas where they fish, to provide extra cover for bass. This is both illegal, and posses threats to the environment beyond your wildest dreams.

3. Make sure that you are not introducing aliens by accident. Always check things like boat props and live wells before leaving an infested area. Check pets that have been hiking with you in areas where noxious weeds exist, to make sure that their fur does not contain any hitchhikers, that might eventualy eat your yard. These are just a few precautionary methods you can use, I am sure you can make other logical extensions.

In light of the potential problems that introducing biological controls might cause, we should, of course, proceed cautiously with the process, chemical control becomes more important, and prevention should be the foundation on which any good IPM program is built.