Integrated Pest Management

Since people first started growing plants for food, we have been battling the pests that eat, damage, or infect those plants. ​

Integrated Pest Management (Santa Fe Parks & Rec)

Initially, those battles were hand-to-hand combat. Pests were removed by hand, chased away, and puzzled over. Then came the age of ‘better living through chemistry’, when powerful concoctions were sprayed willy-nilly, threatening entire species. Now, the pendulum has swung in a new, more balanced direction. That direction is called integrated pest management.

Integrated pest management (IPM) is a program of science-based pest controls with the minimal disruption of natural cycles and least harm to other organisms. Integrated pest management was made a national policy in the U.S. by President Nixon in 1972.

What are pests?

Your younger brother or sister may have been a pest when you were kids, but garden pests never outgrow the potential to cause damage. Garden pests include any organism that can harm or hinder the plants we want to grow. Using this definition, a pest can be disease-carrying bacteria, viruses, or fungi, a plant-eating insect or animal, a competitive weed, destructive soil nematodes, or a neighbor’s cat that thinks your carrot patch is its litter box.

Tomato hornworm (Kate Russell)

What is IPM?

IPM takes a long view on reducing the negative impact of pests in ways that are sustainable and responsible. An integrated pest management plan has six basic tenets:

• monitoring
• determine tolerable levels
• good cultural practices
• mechanical controls
• biological controls
• responsible chemical control

Rather than relying on a single method of control, IPM combines these tenets, in the order presented, to reduce the negative impacts associated with killing off pretty much anything. Rather than spraying chemical pesticides and insecticides on your food plants and into the soil and water table, you can work your way through these sustainable practices for surprisingly effective control of most garden pests.

Monitoring for pests

The first step in an IPM program is monitoring. Monitoring involves more than simply looking for bugs. Monitoring for problems begins by arming yourself with factual information about your soil and microclimate. This means sending out a sample for a soil test. Test results will let you know which nutrients are at acceptable, toxic, of deficient levels, along with soil pH, soil organic matter levels, and base saturations. It also means noting sun and wind exposure levels at various locations in your yard, the likelihood of frost damage, drainage problems, and preexisting pest problems. Each of these conditions play powerful roles in keeping plants healthy enough to defend themselves against pests.

After collecting all that information, go outside and start looking for pests. You don’t know what you are up against without looking. You can use pheromone traps and yellow sticky sheets to help collect information of what costs are present. As you see pests, learn to identify them and then read up on them. Learn enough about them to counteract the damage they do without causing undo damage of your own. This is where things like trap crops come in handy. ​

Monitor pests with yellow sticky sheets

Tolerable levels

The next step is to decide just how much damage you are comfortable with. Wiping out entire species is generally not a good plan. Evolution takes time and the balances that are created can be delicate and easily thrown out of whack. Allowing tolerable levels of pests to be present provides food for beneficial insects which will help you fight the battle against those and others pests.

Cultural practices

Cultural practices are the way you manage your garden. Do you use overhead watering, which can encourage fungal disease, or do you use soaker hoses? Pruning for proper air flow and good structure go a long way toward pest control. There are several good cultural practices that help your plants stay healthy:

• sanitizing garden tools regularly
• disposing of infected/infested plant material in the trash
• promoting proper drainage
• installing plants at the proper planting depth
• selecting plants best suited to your USDA Hardiness Zone and microclimate
• selecting disease-resistant plant varieties
• reducing the introduction of invasive pests and plants​

Protect fruit and nut trees with tree cages

Sticky barriers block pests

Mechanical controls

The third plan of action is mechanical controls. Row covers, tree cages, tomato cages, netting, sticky barriers, brassica collars, mulch, shade cloth, tree supports, trellising, and fencing are common mechanical controls that help plants stay healthy. This stage of pest control also includes trapping, hand picking, and soil solarization. Cold frames, greenhouses, and hoophouses also provide mechanical controls that reduce pest damage by making life harder for the pests.

Praying mantid

Biological controls

There is an army of beneficial insects ready to help you control pests naturally, if you will only get out of their way. Instead of using chemical pesticides and insecticides, which can kill off beneficial predators and parasites, install insectary plants and provide water to create a welcome habitat for the natural enemies of the pests in your landscape.

Other biological controls include the release of sterile insects (generally performed by government agencies and universities) and introducing other natural predators periodically. Unfortunately, buying ladybugs and other predators rarely works as well as you might hope. They generally don’t stick around. Creating a welcoming environment is far more effective. ​I trained my dog to chase imported cabbageworm butterflies out of my yard. I’m not sure if that qualifies as a mechanical or biological control, but it works and it’s fun to watch.

Chemical controls

Before you grab potentially poisonous chemicals to control pests, there are several organic and/or less damaging chemical controls available. Horticultural oils, dormant oils, neem oil, fixed copper sprays, Bordeaux mixture, and sulfur are all effective tools. If you genuinely need to bring out the Big Guns, be sure to read the label and follow it EXACTLY. For one thing, it’s a federal law. More importantly, you can harm yourself by using chemicals inappropriately. Overspray damage on your favorite tomato plant isn’t very fun either.

Chemical pesticides are used as a last resort. Pesticides should be selected as appropriate for the specific pest being controlled and used in ways to avoid affecting non target organisms.

Whichever chemical controls you use, it is important to switch things up periodically to prevent the likelihood of pest resistance. Pest resistance occurs when an organism develops an immunity toward a treatment, making it necessary to use ever-stronger poisons against them. Insects and pathogens evolve much faster than we do, so there is a limit to what we can tolerate.

Finally, after monitoring the situation and deciding which pests can be tolerated, using good cultural, mechanical, biological controls, and applying only necessary chemical controls, be sure to assess the situation, to make sure the problem is being corrected. If it isn’t, you need to go back and learn more about the pest(s) causing the problem to develop a new plan of action.

Generally speaking, pests appear seasonally and on specific crops. Knowing when to look and where to look can give you a jump-start on controlling the pests that damage your garden plants. 

You can help the scientific community by participating in citizen science projects, such s the Big Bug Hunt, where you report insect sightings as you see them. This helps researchers develop better predictions about when pests are likely to appear in your area.