The Philosophy Of Pest Control

In the context of the title of this article, the Concise Oxford Dictionary defines philosophy as "a particular system or set of beliefs". (It also talks about the use of reason and argument in seeking truth and knowledge of reality. However, I think we can dispense with that and stick with the first definition which at least has the benefit of brevity).

Forgive me if the tone of this article has already got you reaching for another coffee, but I have found myself thinking about this topic over the last few days (I know that may stimulate a few mental interjections from readers about my need to get a life, but I can live with that). The reason for my thoughts heading in this direction, is that I have often used the term "the philosophy of pest control" when giving presentations to growers on the use of IPM or biological control. The context has usually been something along the lines of "IPM (and/or biocontrol) involves a change in your philosophy of pest control". And I did it again this week at an IPM workshop. Those words are so used to coming out of my mouth that I seldom stop to really think about what they mean (some may say that is not unusual).

So then, exactly what am I referring to when I use the above words? I am trying to get across, the idea that a shift in thinking is required, when changing from a pest control program based largely on the desire to eradicate pests (an understandable wish considering the objectives of the pests seems to be to eradicate your crops), to one which understands that eradication is not only unlikely, but often impossible.

Let's take a step back. I've mentioned before in this column, the bad old days of calendar pesticide spraying when the spray(s) of choice depended on the day of the week, and eradication was very definitely the goal (not just for growers but for many scientists and researchers as well). A huge leap forward was made with the development of the concept of integrated pest management or IPM, which did not necessarily propose the elimination of pesticides, but instead put forward the argument that they be used strategically along with other common sense control tactics. The major shift in thinking with this approach is that it depends for its success on a crop monitoring program so that the grower understands very specifically what is happening in the crop. Things such as:

• What pests/diseases are present
  
• How many
  
• Where
  
• What damage is being done
  

The grower response may still be to reach for the spray gun, but now it is being used from a position of knowledge. Decisions are made based on the need to take action and not the day of the week; fewer sprays are used and pests and diseases are targeted more specifically. Not only is it accepted that monitoring improves the effectiveness of spray programs, but also there is the realization that not every good insect has to be a dead one. This change in philosophy in the greenhouse ornamentals industry in Canada took place 10-15 years ago and is now well established.

The next step in this philosophical evolution takes place when growers opt for biological control as a component of their IPM programs. Another shift has to take place, one that can be harder to accept than the move from calendar spraying to IPM-based spraying. There is of course the need to acquire new knowledge:

• A better understanding of pest/disease biology
  
• Which biocontrol agents (BCAs) are needed for which pests
  
• How to pronounce the tongue-twisting names of all the BCAs (if it is any consolation, there is no consensus in the scientific world on that either. Put 20 entomologists in a room and you'll get 20 different pronunciations of Eretmocerus eremicus).
  
• Which pesticides can (and cannot) fit into a biocontrol program

However, new knowledge is one thing (after all this is an industry driven by new information and technology). What is more difficult is to hand over the controls of your pest management to tiny insects and mites, to put faith in these little specks of dust.

(There is something very therapeutic in being able to pick up a spray gun, go out into the crop, and direct anger in a concrete fashion at those aphids gathering en masse on the new blooms of mums ready to be shipped. And even if the pesticide does not work as well as it used to, or as well as you'd like it to, there is still the satisfaction of knowing that the sheer force of the spray will let the aphids know who's boss).

And the goal of eradication is not only impossible but it is not even desirable any more. After all, the BCAs need something to feed on. Once the decision has been made to use biological control and the first introductions of predators or parasitic wasps are made, your role changes from a doer to a facilitator (as we would say in government). You can help things along, make sure all the conditions are right, monitor pest and BCA populations every day if you want, but you can't actually control what happens out there when the predator meets the pest. And that is what I mean by a change of philosophy; accepting a new role in your own pest management program.

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