Diazinon: Going, Going, Gone - October 30, 2002
Jeff Schalau, County Director, Agent, Agriculture & Natural Resources
Arizona Cooperative Extension, Yavapai County


The Environmental Protection Agency (EPA) is phasing out a large group of older insecticides belonging to a family called organophosphates primarily because of their potential risk to children. The EPA is taking this action under the Food Quality Protection Act (FQPA). One organophosphate, chlorpyrifos (Dursban), has already been completely phased out for use in home landscapes. Diazinon will be the next organophosphate to be phased out.

Here are some diazinon facts: Over 13 million pounds of diazinon are applied annually. Use is on a variety of agricultural corps and livestock (about 20% of usage), on turf and for residential control of various insects indoors and outdoors (about 80% of usage). For non-ag use, the largest share is in homeowner outdoor insect control for turf and gardens (39%). Other large usage is in lawn care operators (19%) and pest control operators (11%). Indoor homeowner use is also registered. California, Texas and Florida are states with the most significant usage. Diazinon is about 1% of the Pest Control Operator (PCO) market for indoor insecticides.

Specifically, the terms of the diazinon agreement implement the following phase-out schedules:

  • For the indoor household use, the registration was canceled on March 2001, and all retail sales will stop by December 2002.

  • For all lawn, garden and turf uses, manufacturing stops in June 2003; all sales and distribution to retailers ends in August 2003. Further, the company will implement a product recovery program in 2004 to complete the phase out of the product.

  • Additionally, as part of the phase out, for all lawn, garden, and turf uses, the agreement ratchets down the manufacturing amounts. Specifically, for 2002, there will be a 25 percent decrease in production; and for 2003, there will be a 50 percent decrease in production.

  • Also, the agreement begins the process to cancel around 20 different uses on food crops.

Integrated pest management (IPM) strategies will be key in as we make the transition from broad-spectrum insecticides, such as diazinon, to more target-specific products. IPM is an ecosystem-based strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation, modification of cultural practices, and use of resistant plant varieties. Pesticides are used only after monitoring indicates they are needed according to established guidelines, and treatments are made with the goal of removing only the target organism. Pest control materials are selected and applied in a manner that minimizes risks to human health, beneficial and non-target organisms, and the environment.

Correct identification of insects is important to a successful IPM program. For example, various household cockroach species have differing habitat preferences. Cockroach control programs can be enhanced by positive species identification. Once identified, pesticides, sanitation, habitat modification, and exclusion techniques targeted at that species are employed together.

Homeowners that use pesticides will need alternatives to diazinon. For example, insect growth regulators (IGRs) have been developed for control of many household insect pests. These compounds prevent specific insects from becoming sexually mature (preventing breeding) and have little or no effect on non-target organisms. There are excellent IGR products for cockroaches and fleas.

Locally, diazinon has been used effectively to control white grubs that cause dead patches in turf. With the impending phase-out, we will need to find alternative control methods for white grubs. One alternative could be the introduction of parasitic nematodes that live in the soil and feed on the grubs. Homeowners would need to combine this strategy with other control methods, such as trapping adults, to create an IPM approach. No doubt about it, as older pesticides are phased out, we will need to work smarter to reduce insect damage in our gardens and landscapes.

The University of Arizona Cooperative Extension has publications and information on gardening and pest control. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 or E-mail us at mgardener@verdeonline.com and be sure to include your address and phone number. Find past Backyard Gardener columns or submit column ideas at the Backyard Gardener web site: http://ag.arizona.edu/yavapai/anr/hort/byg/.

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Arizona Cooperative Extension
Yavapai County
840 Rodeo Dr. #C
Prescott, AZ 86305
(928) 445-6590
Last Updated: October 24, 2002
Content Questions/Comments: jschalau@ag.arizona.edu
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