Managing Weeds, Insects and Diseases: Effective Best Management Practices (BMPs) that Help Control Pests

Effectively controlling pests - weeds, insects and diseases - is critical to assuring healthy crops. There are many different approaches to managing pests, including preventing the introduction of pests in the first place, optimum timing of activities, crop rotation, mechanical control techniques and even encouraging natural enemies of pests. These various options, along with the judicious and proper use of pesticides, help us manage pests safely, responsibly, and economically - while also protecting our lakes, rivers, and streams, as well as the ground water many of us depend on for our drinking water supplies.

Help Crops Help Themselves

  • Promote tolerance to pests by providing crops with proper amounts of nutrients and water, as well as soil conditions that favor rapid establishment and vigorous growth.
  • Select crop varieties that are resistant to pests and adapted to growing seasons and hardiness in respective areas of the state. (For information on hardiness and resistance to certain pests, refer to the Minnesota Agricultural Experiment Station - University of Minnesota.)
  • Adjust planting dates to optimize crop competition with weeds, minimize insect infestations, and manage other pest problems.
  • Increase ability of crops to compete with weeds by using higher plant population density within recommended ranges, using narrow row spacing, and choosing varieties with dense, rapid growth.
  • Use companion crops, cover crops and crop residues, when appropriate, to suppress weed growth.

Prevent the Introduction and Spread of Pests

  • Consider disease potential when selecting planting sites, dates, and seeding rates.
  • Use disease-free and weed-free seed to prevent diseases and weeds from being introduced.
  • Control alternate host plants of insects and diseases.
  • Minimize moisture conditions optimum for disease development by carefully managing irrigation water applications.
  • Use weed-free feed to prevent the spread of weeds by livestock.
  • Control reinfestation sources of weeds on adjacent property such as fencerows, ditch banks and roadways. (Take care to avoid damage to non-target organisms and threatened or endangered species.)
  • Use good sanitation practices to remove soil, crop residues, weed seeds, and weed parts from equipment before moving to other fields.

Assess the Need for Pest Control

  • Scout fields to properly identify pest conditions and beneficial organism activity.
  • Assess pest population levels, stage of development, and potential for damage.
  • Determine stage of crop growth and plant condition when evaluating the need for, timing and effectiveness of post-emergence pest controls.
  • Observe other conditions, such as fertility problems and soil compaction that may influence the need for action, as well as the type of action needed.
  • Consider economic injury levels (EILs) and economic treatment thresholds when determining whether control is necessary. (For EILs and economic treatment thresholds for certain pests and crops, contact the University of Minnesota Extension office in your county or region.)
  • Select appropriate control techniques, considering effectiveness, cost and environmental impact. Control techniques may be cultural, biological, chemical, or mechanical. An effective pest management program may include aspects of one or combination of these techniques.

Maintain Field Records

Keep field records of pest control activities and pest populations. Field records should include:

  • soil test results
  • crops planted, growth and development, yield
  • pest problems (species present and distribution)
  • controls applied
  • date control applied
  • results

These field records will assist in comparing and evaluating the effectiveness of various pest management techniques. If pesticides are used, read and follow label restrictions and procedures. For more information, contact our licensing unit at 651-201-6615 or visit Private Pesticide Applicator Certification and Pesticide Applicator Licensing.

Rotate Crops and Optimize Timing

  • Rotate crops with different life cycles, growth habits and tolerance to weeds, insects and diseases.
  • Mow or till at an appropriate time to prevent reseeding of weeds and deplete food reserves of perennial weeds.
  • Time harvests to control weed seed production or minimize losses from diseases and insects.

Use Mechanical Control Techniques to Manage Pests

  • Use crop cultivation and shallow tillage operations to control weed seedlings.
  • Pull weeds by hand or use a hoe for smaller, additional, weed infestations. (Don't let them gain a foothold.)
  • Use tillage practices to bury diseased crop residues when appropriate. (These practices may increase soil erosion.)

Encourage Pest's Natural Enemies

  • Consider biological control methods that have been proven effective in controlling perennial weeds, insects, and diseases.
  • Protect natural enemies of pests.
  • Promote the use of natural enemies of pests or their products.