Last Tuesday we talked about two aspects of Integrated Pest Management (IPM): cultural and biological controls. This week we continue the discussion in this Earth-friendly approach to pest control in your garden.

Mechanical Controls

The first mechanical control we have available to us for pest management is hand picking. I don’t know why, but this very simple and environmentally friendly method is often avoided by many gardeners, Here’s the typical scenario.

We get questions all the time asking what can be done about this insect or that weed etc. The person asking the question typically wants us to tell them something they can spray to eliminate the problem. I understand, but oftentimes the simplest approach is the best: hand removal. For example, if you happen to have tomato hornworms devouring your tomatoes, you can just put on your gloves, pick the hornworm off your plant, and then dispose of the caterpillars. Simple, to the point, and no other insects were harmed in this procedure. For many smaller insects, a strong stream of water is enough to get them off your plants and out of your hair.

Pruning is another example of a mechanical pest control. Assume you discover you have powdery milder showing up on one of your plants. If you catch it in the initial stages, you can just prune out the affected leaves and the problem is oftentimes solved. I have done this with crape myrtle bark scale before. Upon noticing this scale on a few branches, I just pruned out those branches and was done with it.

Some pests can be kept from your plants with a kind of mechanical barrier such as a cage or mesh. Many a gardener in more rural areas have fences around their gardens to keep the deer away, but you can also suspend chicken wire or mesh over your plants to keep birds from eating your strawberries for example.

Last in the mechanical controls would be traps. There are a variety of sticky traps or pheromone traps that are appropriate for garden use. Just place the trap near the problem, and many times this will be all you need to do. Once again, there is absolutely no negative environmental downside to this strategy.

Chemical Solutions

As the last resort in IPM we turn to chemical pesticides, but there are a wide variety of pesticides available, so which ones do you choose. There are several “kill every insect in sight” pesticides and we generally discourage their use since they do not discriminate. Pesticides that are appropriate for IPM practices are typically organic and target a specific class of pests.

For example, bacillus thuringiensis or Bt is an organic pesticide that is very effective against caterpillars. It is a derivative of a soil bacteria and when the caterpillar eats it, it makes them sick and they stop eating. It has no effect on other insects.

Neem oil is another good organic option. Made from oil found in the seeds of a neem tree, this organic pesticide is the swiss army knife of pesticides. As a horticultural oil it works by smothering insects when applied directly to them. It also has repellant properties and as an extra bonus neem oil works well as an anti-fungal.

Another good pesticide to keep in your IPM arsenal is insecticidal soap. Insecticidal soap is a mixture of soap and water - nothing harmful there. It is a contact pesticide that kills pests by suffocation. It also disrupts the cellular membranes of the insect by removing protective waxes. It is quite effective against aphids, some scales, whiteflies, mealybugs, thrips, and spider mites.

On the internet or perhaps gardening sites on social media you will see a variety of recipes using standard dish soap and water as an insecticidal soap. We try to discourage people from doing this because commercial dish soaps contain a variety of chemicals to help degrease and clean your dishes. These chemicals can oftentimes be detrimental to your plants. True insecticidal soap contains two ingredients: potassium salts of fatty acids and water. In other words: soap and water. Insecticidal soap is not expensive, and my recommendation is that you spend a few dollars on the real thing rather than tempting fate by spraying the mulligan stew of chemicals you find in dish soap on your garden; especially things you are planning on eating.

Other good examples of organic, targeted pesticides are spinosad and pyrethrin. You can find more information on organic pesticides on our website tulsamastergardeners.org.

And one more thing while we are talking about pesticides; always read the label. Yes, I know we usually do that as a last resort but if you know how to best use them going in, you are going to get better results. Each pesticide will also talk about “days to harvest” or “pre-harvest interval”. This is critical information as it tells you how soon you can use a pesticide before harvesting. For the most part, synthetic pesticides have a longer pre-harvest interval than organics. So, read the label.

The Path of Least Resistance

And last but not least, you always have the option of doing nothing about your pest problem. Many gardeners (including myself) try our best to utilize this strategy. It may take some self-control because our natural instinct seems to be to try and fix the problem. But, we need to remember these insects are just doing what they do: eating, growing, mating, having kids, and then starting all over again. For example, the tomato hornworm is eating your tomato plant like crazy because it wants to become a beautiful moth. So, if you want to be completely earth-friendly, just plant enough for everybody. Good luck.

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.