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National Pesticide Information Center

npic@ace.orst.edu

1.800.858.7378

Plant-Pesticide Interaction

Pesticides can be absorbed by plants through the leaves and roots. Pesticides that are taken up by plants can move (translocate) to other parts of the plant.

  • Herbicides that are taken up by the plant (systemic herbicides) often are designed to interfere with the plants development by mimicking plant hormones. This type of herbicide can take longer to act, but they can also be more effective because they are working throughout the plant. Other herbicides are meant to kill by contact. These types of herbicides tend to act faster - you may see an immediate "knock-down" of the weed.
  • Systemic insecticides move throughout the plant. When insects feed on the plant, the insecticide can kill them. This type of insecticide can be harmful to bees and other pollinators. When the bee is pollinating the plant, it may also receive a toxic dose of the pesticide. It is important to read the label and use this type of product only when it will not pose a threat to the pollinators.

Here are some tips to help minimize environmental risks when using pesticides on plants:

  • Read the pesticide label, including the "Environmental Hazards" section, and make sure you are using the product properly to minimize the risks to the environment.
  • Consider adopting an IPM approach to controlling pests. IPM practices are designed to have minimal impacts on the environment.
  • When possible, try to use pesticides that are specifically designed for the pest you are trying to control, rather than broad-spectrum pesticides, which are more likely to affect non-target organisms.
  • Always dispose of unused pesticides properly.
  • Insects, weeds and diseases can become resistant to pesticides that are used repeatedly. As such, it is important to use pesticides only when necessary, and only as often as the label indicates.

If you have questions about this, or any pesticide-related topic, please call NPIC at 1-800-858-7378 (8:00am - 12:00pm PST Mon.-Fri.), or email us at npic@ace.orst.edu.

Additional Resources:

Resistance

Last updated October 8, 2012