Pesticide recommendations

ALWAYS read and follow the instructions printed on the pesticide label. The pesticide recommendations in the PNW Insect Management Handbook do not substitute for instructions on the label. Pesticide laws and labels change frequently and may have changed since this publication was written. Some pesticides may have been withdrawn or had certain uses prohibited.

Use pesticides with care. Do not use a pesticide unless the specific plant, animal or other application site is specifically listed on the label. Store pesticides in their original containers and keep them out of the reach of children, pets, and livestock.

By law, applicators of pesticides must have in their possession current product labels and must use pesticides in a manner consistent with label directions. If, for any reason, directions given in this publication are not consistent with the label, the pesticide labels always take precedence over entries contained in this handbook.

The following are exceptions to this under current EPA definitions. It is legal to apply pesticides in any of the following ways:

  1. More dilute than on the label
  2. At a lower rate than on the label
  3. Less frequently than on the label
  4. For pests not on the label, as long as the site or crop is listed and other restrictions are observed

It is illegal to apply pesticides in the following ways:

  1. Using less diluent (water) than on the label, thus increasing the concentration
  2. At a higher rate per acre than on the label
  3. Shortening the specified interval between applications
  4. Shortening the preharvest interval (minimum number of days between the last application and crop harvest)

Pesticide Registration—Pesticides are registered federally under Section 3 of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) as amended in 1972, 1975, 1978, and 1988. This law also permits registration (Section 24c) within states under certain conditions to satisfy special local needs.

Because 24c uses are state-initiated, they usually are not provided on container labels but are listed on supplemental labels, provided by the dealer or manufacturer (through their website). If a 24c application is made, the pesticide applicator possesses the appropriate 24c label. These uses are identified in the handbook as 24c with the state or states holding the registration identified.

A third type of registration (Section 18) permits, at the discretion of the administrator of the EPA, special emergency exemption from the provisions of FlFRA-amended. These emergency uses are so ephemeral, limited, and unpredictable that they are not included in this handbook. Print-on-demand labels and Special Local Need (SLN 24c) documents for many currently registered pesticides are available from the following website:

Trade Names—To simplify information, trade names are frequently used. No endorsement of named products is intended nor is criticism implied of similar products not mentioned. While pesticide products listed in this handbook are legally registered pesticides, this in no way guarantees efficacy in all circumstances and in every geographical area covered. Pesticide resistance in local areas may render some products ineffective.

There may be insecticide names, formulations, and rates labeled for pests or sites that are not included in the handbook. Conversely, not all labels for a given product may include every pest mentioned. It is the responsibility of the user to comply with label directions on the product applied.

Developing a format for the use of trade and/or common names in the handbook that would be most useful to the reader has resulted in compromise. The common name is used alone when it is well known. Otherwise, trade names and common names occur together for clarity. The Acute Toxicity Data section of the handbook lists common names, sample trade names, and chemical definitions of insecticides. Due to the rapidly changing nature of labels and trade names, omissions may occur.

The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this handbook, implies no endorsement by the authors or the Extension Services of Oregon, Washington, or Idaho. Criticism of products or equipment not listed is neither implied nor intended.

Due to constantly changing labels, laws, and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied according to the label directions on the pesticide container.

Groundwater—To protect groundwater, when there is a choice of pesticides, the applicator should use the product least likely to leach.


As of 12/20/20, the State of Oregon has adopted new restrictive rules on the use of chlorpyrifos-containing products in Oregon. Please refer to Oregon Department of Agriculture Permanent Chlorpyrifos Rule at

As of 02/28/2022, chlorpyrifos tolerance for all food commodities expire according to the final rule of the Environmental Protection Agency (EPA). EPA will continue to evaluate the non-agricultural, non-food uses as part of the ongoing registration review for chlorpyrifos, which is expected to be completed by the statutory deadline of October 1, 2022.