To be sure, the hardest part of employing IPM in the landscape is learning to relax. We have all been conditioned to reach for the pesticide as soon as an evil bug appears on our beloved plants. Now we're being told we have to actually watch and do nothing while aphids chow down on our roses?!?
Well, yes and no. But doing nothing is always the preferred choice of action in IPM, much as gardeners hate to hear it. However, if doing nothing eventually results in your $100 brugmansia being covered with mealybugs, you need to form a plan of action by climbing what I call the IPM Action Ladder.
The first rung of the IPM Action Ladder is, again, doing nothing. Let's say you spot a single squash bug in your veggie garden, but there's no sign of damage (yet), no evidence of egg laying, no hungry little squash bug nymphs, nothing. You also see a big robin lurking around the veggie garden. In this case, make a mental note to keep an eye on the area where you saw the squash bug, but don't panic. Tell the robin he is free to dine on squash bugs whenever he likes.
A week later you see five squash bugs along with some wilting and sucking damage evident on a few leaves of your zucchini, plus some squash bug eggs. At this point, advancement to the next rung of the Action Ladder is advisable in the form of mechanical control.
Pluck the adult bugs off with a gloved hand and throw them in a bucket of soapy water to kill them. (Or better yet, tell your kids you'll pay them a quarter for every squash bug they pick off and kill.) Remove any leaves with damage and/or eggs and throw them away.
You may want to consider covering the plants with a row cover at this point. Or maybe try sticky traps. Or use what is called a repellant plant, such as marigolds or radishes, around the crop plants.
As always, be sure to keep your garden area clean by picking up and disposing of all dead plant debris.
Ok, a week passes and you see two squash bugs, no eggs and no additional wilting or damage. Congratulations - the situation hasn't gotten worse, and that's a good thing. You pluck the two remaining offenders off, destroy them and celebrate your success. Continue to keep an eye on the area, however.
How about a more drastic situation? For example, you go on vacation for two weeks and return home to discover that the squash bugs have now rented your vegetable garden out to all of their friends and relatives. Emergency measures are certainly called for, but continue to resist the urge to reach for the most powerful stuff you can find. Instead, identify exactly what pests you're dealing with and do some research into what the least toxic pesticide is targeted to control them. A blast from the hose or a release of lady beetles may do a world of good.
Personally, my pesticide cabinet is pretty empty. I'm at a happy point where I just don't use very many pesticides, because a nice balance has finally been achieved in my gardens. Spiders, wasps, lady beetles and birds are welcome and plentiful since I don't use harsh chemicals that could harm them. As my reward, these wonderful creatures keep most of the bad bugs in check in my yard. When I do have a pest problem, it's usually my fault; I've let a plant get root bound in a too-small pot, I've neglected to water properly, etc.
As for the pesticides I do use: I find the oils, such as horticultural and Neem, to be wonderfully effective on sucking insects. If you go this route, be sure to only spray oils during the cooler part of the day when they can't burn plants or harm honeybees. Insecticidal soaps are also good (especially when combined with the oils) and very mild. For slugs, use iron phosphate pellets (like Sluggo or Escar-Go!), which rank very low in toxicity, so they're safe to use around people, pets and edibles. For caterpillars and fire ants, use Spinosad.
And please, this message always bears repeating: follow the label instructions on whatever garden substance you're using. Don't think stronger or more is better. Actually, I often make my mixes weaker than what's recommended to see if it will be effective at a less toxic level. Many times, the weaker solution is just as good.
In summary, know that IPM is only tough in that it asks you to show restraint, and to climb that Action Ladder one rung at a time whenever possible. That's good advice in many aspects of life, isn't it?