IPM: Smart pest management for the vegetable garden

Integrated Pest Management (IPM) is an integral part of a smart garden.

Keeping pests away from cole crops, such as this kohlrabi, can be as simple as placing a row cover over for protection. Photo credit: Mary Wilson, MSU Extension

Keeping pests away from cole crops, such as this kohlrabi, can be as simple as placing a row cover over for protection. Photo credit: Mary Wilson, MSU Extension

Smart Gardening LogoWhat is IPM and why is it smart?

IPM stands for “Integrated Pest Management.” The principles of IPM can be applied to managing a lawn or landscape, pests in a home or producing food in a vegetable garden. IPM uses a series of common-sense steps to manage pests and optimize plant health. The term “pest” includes insects and mites, diseases, weeds and animals. Using IPM to manage garden problems is smart because it incorporates a variety of methods that are economical and effective to keep plants healthy and achieve a bountiful harvest. While IPM takes advantage of all appropriate pest management options including judicious use of pesticides, by incorporating a variety of methods it is possible to reduce or eliminate pesticide applications while still addressing garden problems. Smart gardeners use IPM to protect human health and the environment by making more environmentally-friendly pest management choices.

Are IPM and organic methods the same thing?

No. Although organic food production applies many of the same concepts as IPM, it restricts the use of pesticides and fertilizers to those that are produced from natural sources instead of allowing synthetic chemicals.

Steps to following IPM

Identify pests and understand their lifecycles. Only a few insects are actually pests; many are beneficial or do no harm. Take time to identify beneficial insects and pollinators. For help in identifying insects and diseases, call the toll-free garden hotline at 1-888-678-3464, or send samples to MSU Diagnostic Services. For information on how to send samples and a list of available services and fees, visit www.pestid.msu.edu.

Stages
Different life stages of a beneficial lady beetle: larva, pupa, adult. Photo credit: Bugwood.org: Larva - Frank Peairs, CO St U, pupa and adult - Russ Ottens, UofGA

Learn how to identify common pests and pest damage on vegetables. Understand that different life stages of pests do not look alike and that not all stages cause damage or can be managed. By understanding their lifecycles, you learn the best timing for successful management strategies.

Scout for pests. Check your garden regularly for insects and diseases and make written records of what you find. Jotting down the information in a garden journal is helpful instead of relying on memory. Keep a magnifying glass or hand lens handy to see more details for better identification. Use the information collected to help you plan pest management for the following year. Yellow sticky cards placed just above the plant canopy can be helpful for detecting some insects.

Be realistic with IPM: prevent or limit damage. Once you have identified a problem, determine what options you have for managing it. Some pests are more damaging than others. Establish tolerances for pests and pest damage. Don’t expect vegetables to look picture perfect. Some insect damage can be tolerated and will still allow a good quality vegetable harvest. In general, diseases are best managed by preventing them; many cannot be easily controlled once they are established.

Implement your IPM Program. Select effective and environmentally-friendly methods, such as the examples given below. Record what worked and what didn’t, and make adjustments accordingly.

How to implement IPM in your vegetable garden

Right plant, right site. Vegetables grow best in well-drained soils and full sun – a minimum of six hours a day, ideally eight to 10 hours. Avoid low areas where cold air settles as plants are more prone to frost damage in these locations. Get a soil test to find out about soil pH, needed nutrients, organic matter content, soil type and to receive recommendations to improve the soil. You are aiming for a soil pH of around 6.5 and an organic matter content of 5 percent or more. Knowing your soil type, whether it is sandy or contains a lot of clay, enables you to make decisions to improve the garden area. Supply missing nutrients for the garden; add compost or composted manure for organic matter, not as a fertilizer substitute.

Michigan State University Extension recommends testing the soil before starting a new garden and retesting every three to four years. The Gardening in Michigan website has good resources for additional information on growing specific vegetables.

Start with healthy plants. Buy well-branched, stocky transplants with healthy leaves, sturdy stems and well-established root systems. Transplants need good root systems to quickly establish in the garden. Roots should be well formed, white and hold the soil mass together. Avoid older transplants with flowers or fruit as this will limit yields. Reject plants with soft, brown or rotten roots. Select varieties with multiple disease and insect resistance or tolerance, if possible.

Employ environmentally-friendly pest management methods

Use good sanitation practices. Keep tools and equipment clean by using a solution of 10 percent chlorine bleach to disinfest tools after using them on diseased plants. Keep plantings clean by removing and destroying diseased plants or those that are severely infested with insects during the growing season. Do not compost – burn or bury instead. Remove crop residues at the end of the growing season. This can be a place for certain garden pests to spend the winter. Control weeds all year long. Weeds compete with crops for water and nutrients and often provide a place for pest insects to hide and a good environment for disease organisms.

Crop rotation. If space is available, rotate the location of the garden every few years to avoid the buildup of plant diseases and insects. The least you could do is rotate the location in the garden among plant families. For example, the nightshade or Solanaceous family is made of tomatoes, peppers, eggplant and potatoes. They share several insect pests and diseases, so rotating the family to different locations from year to year can lessen or prevent problems.

Weed management. Start with a clean seedbed. Limit herbicide applications to spot treatments or application prior to planting. A cover crop of annual ryegrass or spring oats sown in late summer or fall will help keep weeds out of garden areas and increase organic matter. The cover crop should be tilled into the soil about a month before planting in the spring. Hand pull, cultivate soil or hoe to control weeds. Eliminate weeds before they go to seed. Apply organic mulches after the soil warms to keep weeds down and retain soil moisture.

Straw
Using straw as organic mulch will help manage weeds. Photo credit: Rebecca Finneran, MSU Extension

Insect and mite management. Use insecticidal soaps and horticultural oils on soft-bodied insects and mites. Always follow label directions for application and use only insecticides that are registered for the crop. Hand-pick larger insects such as potato beetles and tomato hornworms. Japanese beetles can be knocked off plants into a container of soapy water to drown. Gardens managed with minimal insecticides often have abundant natural enemies present to help keep some insect pests at bay. Create refuges of nectar and pollen plants for beneficial insects nearby. Floating row covers can be used to exclude insect pests, but will need to be removed before pollination can take place.

Disease management. Diseases are best managed by prevention rather than treatment. Select disease-resistant vegetable varieties and avoid working in the garden when plants are wet as it can spread diseases. Although we can’t control when it rains, we can take charge of when we irrigate. Watering late in the day leaves plants wet overnight, setting up favorable conditions for many fungal diseases. When watering is needed, use drip irrigation or soaker hoses instead of watering overhead. It keeps leaf surfaces dry, making conditions less favorable for most diseases, and is more economical. Water is directed where the plant roots can use it, not sprayed up into the air where it evaporates.

Give plants enough space to grow by thinning seedlings to avoid overcrowding. Crowded plants tend to be weaker and more stressed, making them more vulnerable to diseases. Stake plants and use mulches to keep fruit off the ground. Among the plants that benefit from not laying on the ground are tomatoes, peas, pole beans and cucumbers.

IPM for animal pests

If you have problems with deer, rabbits or woodchucks, it may be necessary to construct a sturdy fence to keep them out of the garden. Some people have difficulties with raccoons or squirrels, so try to determine what your garden critter is so that something appropriate can be constructed. If the animal pest digs, you may want to bury a portion of the fence in the ground so digging does not lead to a food reward. Bend the bottom portion of the fence into an “L” shape and bury it. The underground “wing” will prevent digging under the fence. It is also possible to construct an electric fence with the same parts used for farm livestock except put the bottom of the fence only several inches off the ground. Check local regulations to determine if electric fencing is permitted in the community where you live. Do not forget about putting up a gate that closes tightly.

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