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Stormwater Pollution Prevention

Stormwater Pollution Prevention


We all want our homes and gardens to be beautiful and healthy, but insect pests can be a difficult challenge. Many people use chemical pesticides to control pests. Stormwater testing in Modesto has shown that some active ingredients in these pesticides, especially diazinon and chlorpyrifos, are occurring at levels that could threaten our health and the health of our rivers, ponds, creeks, and wetlands. The testing also shows that most of these pesticides come from Modesto's residential neighborhoods. We can reverse the situation. We just need to learn different methods for controlling our pests. This guide provides some general tips as well as alternative methods for treating the most common pests found in Modesto's homes and gardens.

Know before you spray:

Do you really need to use a pesticide? Low numbers of many garden insects can be tolerated and help build up numbers of beneficial insects. If insects numbers exceed tolerable levels, properly identify the pest and choose the least toxic pesticide that can effectively control it. Pesticides include insecticides, herbicides, and fungicides, which kill insects, weeds, and control plant diseases.

  • Use the least toxic product that will do the job.
  • Choose the right pesticide for the job.
  • Read label instructions carefully.
  • Watch the weather.
  • Water carefully.
  • Ask questions.
  • Consult the Resources section of this guide.

Call the UCCE office at (209) 525-6800.

Proper Pesticide Disposal:

When you have finished using a chemical pesticide, clean up properly so that pesticides stay out of the storm drains, waterways, and sewers. Follow label instructions.

Pesticides will remain in the bottom of your applicator when you finish spraying, even when you do a great job of estimating the quantity. Dilute these residues with clean water and respray in your garden until the solution is used up. Then dilute again and respray or broadcast on the ground. Finally, do this a third time. Be sure that this spray can't drain into the street or gutter. Never rinse containers into the gutter (part of the storm drain system) or household drains (to the sewer system).

Take unwanted pesticides or pesticide containers to a Cities and County of Stanislaus Household Hazardous Waste Collection Event. Call (209) 525-4123 for more information and a schedule. Never throw pesticides or containers with pesticides into the garbage.

The IPM Approach:

Integrated pest management (IPM) methods provide less-toxic or non-toxic home landscape and garden care. IPM focuses on identifying the conditions causing pest problems, changing the conditions to discourage recurrences, and selecting controls that minimize health and environmental risks. Call your UC Cooperative Extension office at (209) 525-6800 of look on the web at for more information about IPM for specific pests. Tell your landscape and nursery professionals that you are interested in less toxic, IPM methods.

  • Plant SelectionSelect Plants that are adapted to Modesto, including natives and disease resistant varieties.
  • Plant HealthProvide the proper amount of food, drainage, light, and water to reduce pest related problems.
  • Garden and Home HygieneRemove pests' hiding places (leaf piles, animal wastes, rotting fruit, standing water) and sources of food.
  • Create barriers and try trapsTry netting or plastic covers for plants. Sticky barriers prevent insect movement. Traps are helpful in roach management. Plug entry holes for ants.
  • Beneficial InsectsBeneficial insects eat pests. See the examples in this guide. Encourage beneficials with flowering plants (food source) and plant variety (adequate cover). Some beneficials can be purchased from retailers and mail order firms.
  • Physical RemovalPull weeds and remove pests by hand. Try a hard spray of water to knock insects from leaves.
  • Less Toxic InsecticidesWhen insecticides are needed, there are many products that pose few health and environmental hazards. These include insecticidal soaps, insecticidal oils, microbially-based products like Bacillus thruingiensis, insect-eating nematodes, and botanical insecticides such as pyrethrins and neem, that are derived from plants. It is essential that you chose the right product for your pest.
Pest Management Guide Look for this guide at a local nursery

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