How to Time and Apply Pesticides

Summer brings gorgeous blooms, green grass and bright gardens, but it also brings frustrating pests. Although many pests can be controlled through natural methods, sometimes a pesticide is necessary. Pesticides include any substance that prevents, destroys or repels weeds, insects, fungi or other pests. Although all pesticides are different, there are several rules of thumb you can follow for proper application and timing.

Pesticide Timing

Postinfestation Pest Management

Unless you have known and heavy pest infestations, postinfestation pest management is the preferred control method. With this method, pesticide is applied after the pest has appeared. This allows you to monitor the pest, determine whether pesticides are needed and choose the best pesticide for the situation. You should use postinfestation pest management in the following situations:

  • You are unsure whether weeds, insects or fungi will appear or be problematic.
  • Annual weed, insect or fungi problems are not serious and you can wait to decide which pesticide to use.
  • You are not sure what kinds of weeds, insects or fungi will appear.

Preventive Pest Management

In preventive pest management, pesticide is applied before an infestation, such as using herbicide in early spring before weeds appear. To avoid overusing pesticides, only use preventive pest management when you experience one of the following:

  • Known and recurring heavy annual weed populations
  • Known and recurring insect infestations (or high likelihood of an infestation)
  • Conditions (such as hot, humid weather) that make fungal infections of plants likely

Other Timing Considerations

As a rule, apply pesticides on a calm day when temperatures are between 60 and 85 degrees Fahrenheit. Use pesticides in the morning to avoid high winds and hot temperatures. Depending on the pest, pesticides can be more effective when used during specific stages of the life cycle. For example, control dandelions (Taraxacum officinale), which grow in U.S. Department of Agriculture plant hardiness zones 3 to 10, before they set seed to prevent them from spreading.

Ready-to-Use Pesticide Application

Step 1

Read the pesticide label carefully and follow all instructions. Each pesticide is different and can have unique instructions for its use.

Step 2

Put on protective clothing, including a hat, long-sleeved shirt, long pants, neoprene or unlined rubber gloves, socks, unlined boots and goggles or other eye protection. Cover all exposed skin.

Step 3

Remove all pets, children, dishes, food and other items that could become contaminated from the area. Cover fish ponds or outdoor aquariums. Do not return these to the area until the recommended period on the pesticide label has passed.

Step 4

Cover any desirable nearby plants with plastic to protect them from harm if you are using an herbicide.

Step 5

Attach your garden hose tightly to the sprayer bottle if the instructions recommend it. Set the sprayer settings as described and turn on the faucet. Spray from a distance of 12 inches, covering the application area evenly and thoroughly, including the undersides of leaves. Completely coat the surface of the plant, but do not allow the pesticide to drip.

Step 6

Remove the clothes you wore to apply the pesticide and shower with soap and water when you are finished. Wash the clothing you wore separately from other laundry, using hot water and detergent. Clean your washer by running a cycle without clothes, using detergent and hot water.

Pesticide Spill Cleanup

If you accidentally spill pesticide, turn the container upright and cover any spilled pesticide with newspaper, cat litter, paper towels or another absorbent material. Keep children and pets out of the area until the spill is completely cleaned up.

Sweep up the contaminated materials and place them in a heavy-duty plastic bag. Clean the area using detergent and a small amount of liquid, and absorb it using paper towels or other absorbent materials. Place these materials in the plastic bag as well, seal the bag and place it in the trash. Place any other items you used to clean up the spill in plastic bags and throw them in the trash.

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