If you’ve been playing along, this is the third and final article in our series about how to deal with garden pests and disease in environmentally friendly ways. To accomplish this, we’ve been talking about a strategy called Integrated Pest Management or IPM for short.

In the first article we talked about Cultural Controls or basically modifying our approach to gardening through practices that help minimize the chance for disease. Cultural controls would include choosing disease resistant plants, providing healthy and appropriate growing conditions for our plants, removing diseased or damaged branches or plants, keeping our tools disease free by cleaning them with a 10% bleach solution, rotating crops, and utilizing garden mulch to minimize the ability of disease to migrate from the soil to the plant.

Last week we talked about Biological Control methods such as using good bugs to defend against the bad bugs. Yes, I know, calling them bad bugs is a little harsh, but if they are eating my tomatoes, they are officially on my bad bug list.

The biological control strategy would include adding lady beetles to our gardens to help when we have aphid problems. In addition, it’s good to have a variety of healthy, blooming plants in our landscape to attract a variety of insects so that we have more good bugs to naturally take care of the less than desirable bugs.

And last but not lease, it’s a benefit to make our landscape bird-friendly, since birds love to eat caterpillars. Now for the final two strategies which include Mechanical/Physical and Chemical controls.

Mechanical/Physical control is pretty much what it sounds like. It’s old school in a variety of ways. For example, suppose you have an insect dining on your vegetable plants. You can just hand-pick the insects off the plant. For a more specific example, let’s say we have a few tomato hornworms eating our tomato plants. If you don’t want to share, you can just pick them off and dispose of them. It doesn’t get much more environmentally friendly than that. This would also work for a variety of other insects including squash bugs. Squash bugs can be eliminated by “squashing” them between your fingers. This would work on groupings of squash bug eggs as well. Just know that squash bugs can emit an unpleasant smell when you crush them. If this up close and personal strategy is not your thing, you can just cut off any leaves where you find squash bug eggs and throw them away. This “hands-on” approach works for a variety of insects.

Next up is aphids. Aphids are very small and not very strong, so to remove them from a plant you can use a strong stream of water. Spraying the areas of a plant with water where the aphids have taken up residence will remove the insects and minimize the problem. They’ll never make it back to the plant.

If it’s a disease problem on your plant, removing the infected portion of the plant and throwing those parts away can go a long way toward keeping the disease from spreading to the entire plant. This doesn’t always work, but it’s a good place to start.

For larger potential pests such as squirrels, birds, rabbits, or deer, a physical barrier works well. A physical barrier would include cages around your plants made of chicken wire or some other type of of mesh or a fence in some cases. You just don’t want to seal the plants completely off. Any mesh or cage would need to have openings large enough for the pollinating insects to get through.

And lastly, you can use sticky or pheromone traps. Insects will be attracted to the traps and get stuck, unable to make their way back to the plants. Sticky traps in your garden will not discriminate between the good and bad insects, so use them as more of a diagnostic tool than a main line of defense.

If none of these methods are able to accomplish the task, there are a variety of organic pesticides that work great in the garden. Just remember to spray early in the morning or later in the evening to minimize potentially affecting the pollinating insects we want in our gardens.

When using pesticides, we want the pesticide to be target specific rather than what I call the nuclear option that will kill any, and everything. A variety of our organic pesticides are very target specific. For example, bacillus thuringiensis or bT for short. BT targets caterpillars. The caterpillars ingest bT, it makes them sick, and they quit eating. It is not a threat to non-caterpillars.

We also want our pesticide to break down quickly. We don’t want to spray something that lasts for several weeks, killing everything that comes into contact with it. We want it to help solve the problem and then go away. Pesticides that break down more quickly also pose less threat to humans.

We also need to be aware of something called the Pre-Harvest Interval for a particular product. The pre-harvest interval is the number of days between when you can use the product and safely harvest and consume the vegetable. For many of the organic pesticides, the PHI is a day or so. This is much better than some of the synthetic pesticides that have a PHI of two or three weeks. Organic pesticides would include insecticidal soap, pyrethrin, spinosad, neem oil, and bT.

This concludes this series of articles on Integrated Pest Management. If you would like to learn more about vegetable gardening including IPM, we still have some spaces available for our final vegetable growing class of the year. The class is called our Urban Gardener/Seed to Supper class. It will be Saturday July 20^th from 9:00 am until 3:00 pm. In this class we’ll cover soil nutrient management, types of gardens, seed starting, planning your garden, harvesting, and dealing with pests in an environmentally friendly way. Visit our website (www.tulsamastergardeners.org) for more info and to sign up. See you in the garden.

You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th Street, or by emailing us at mg@tulsamastergardeners.org. Photo: 

Whitney Cranshaw, Colorado State University, Bugwood.org