In the northwestern U.S., Washington State University Extension's Forest Health Notes states that the focus has shifted from using pesticides to taking preventive measures:
Excerpt:
Control methods have shifted away from direct control (e.g. spraying, felling, burning) and towards prevention of outbreaks. This course of action was chosen after thoroughly exploring direct control measures for nearly a century and arriving at a simple conclusion: They don't work. It is possible to prevent infestation with penetrating sprays on individual, high value trees such as those in campgrounds and near houses, but they need to be applied before the tree is infected and the cost of such treatments is prohibitive for any large-scale application.
Once a mountain pine beetle outbreak begins to spread, it can be stopped by thinning the stand ahead of the edge of the outbreak. This is because outbreaks expand on a tree to tree basis where the incoming beetles switch their attacks from a recently attacked-stem to the next largest tree. More importantly, infestations can be prevented by thinning stands before crown closure, an operation that not only increases the vigor of the residual stand, but also prevents the spread of an outbreak if individual trees have been attacked.
Mountain pine beetles are a natural part of western ecosystems, and for this reason will never be completely eradicated (nor should they be, as they serve to create small stand openings which are important for biodiversity of both flora and fauna). As such, the death of a few trees on your property doesn't necessarily mean an epidemic is getting started; check your trees for root disease symptoms. To maintain mountain pine beetles at their normal levels, predisposing factors for outbreak must be removed. Some of these, such as environmental stresses, are not possible to control. However, many stresses are related to stand management practices. First and foremost, two situations need to be addressed: root disease centers and overstocked stands. More details about treatment for root disease centers have been given in other WSU Cooperative Extension "Forest Health Notes;" in summary, they need to be identified and planted with resistant species. Overstocking causes trees to compete for water, light and nutrients, and thus weakens their defenses against bark beetle attack. To minimize stand stresses and maintain vigorous growing conditions, stand managers should: (adapted from Berryman: Forest Insects, 1986).

The Canadian Council of Forest Industries (CCoFI) has a task force on the mountain pine beetle. You might want to contact them for the latest update. Go to their mountain pine beetle website and follow the links for additional information, including how to contact CCoFI.

Season All Season
Date 2007-12-06
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Do you know which weed and feed product was used? That would help in determining the chemical's half life (persistence) in the soil. Regardless of which chemical was used, my recommendation would be not to plant any edibles in a site which has been treated with weed and feed, but to find another location for your food plants (such as containers made of safe materials, or raised beds with a barrier between the bed and the chemically treated area of the garden).

Local garden writer Ann Lovejoy has discussed weed-and-feed products in her column. Here is a link.

Here is what retired Washington State University Extension agent Mary Robson had to say on this subject in one of her columns:

Just one note of caution-be careful with all chemicals. Many pesticides ordinarily used in gardens are not allowed on edibles. An example is Lawn Weed and Feed which will harm any broadleaf plant whether lettuce or marigold or petunia. It's probably safest to keep pesticides out of the garden if you plan to eat the produce.

From Washington Toxics Coalition:

The Hazards of Weed and Feed

Weed and feed is a mixture of lawn fertilizer with weed killer, usually 2,4-D and related compounds. The problem with weed and feed is that it is designed to be applied to the entire lawn regardless of whether or not weeds are actually present. This encourages over use. For example, if 30% of your lawn is covered in weeds, 70% of a weed and feed application will be wasted, since the herbicides have no residual action. Since many people do not realize that weed and feed is a pesticide, they may be less inclined to read an follow label instructions. For example, did you know that it is illegal to apply weed and feed more than twice per year on the same site?

The herbicides in most weed and feed products are mobile in soils and are widely found as pollutants in local streams, according to the U.S. Geological Survey. In addition, 2,4-D is neurotoxic and may be a carcinogen according to some studies.

Weed control should be practiced only as needed, not every time you fertilize. Mechanical controls are preferable to protect health and the environment. If chemical controls are used, spot treatment should be utilized to minimize product use and resultant risks from direct exposure and track-in to the home on shoes and feet.

Here are links to information on some common weed-and-feed type products and their hazards:

From the Pesticide Action Network North America

From the Journal of Pesticide Reform

Season All Season
Date 2008-02-07
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It would be best if you could avoid using pesticides to control sod webworm. If you can encourage natural predators in your garden (such as ants, ground and rove beetles, parasitic wasps, and particularly birds), this should cut down on the infestation, whereas pesticides may well have a deleterious effect on beneficial insects and wildlife. University of California, Davis Integrated Pest Management also suggest that reducing thatch, and proper irrigation and fertilization of lawns will cut down on infestations of sod webworm.

Covert is a synthetic pyrethroid (as opposed to a natural pyrethrin). You may have already looked at the Material Safety Data Sheet for this product, but in case you have not seen it, here is a link. This document lists the product as highly toxic to bees, extremely toxic to fish and aquatic life, and notes that it contains ethyl benzene, a confirmed animal carcinogen. The Northwest Coalition for Alternatives to Pesticides also has information about the toxicity of permethrin (an ingredient of Covert). Here is more on permethrin and pyrethroid insecticides. Essentially, synthetic pyrethroids last longer in the environment than pyrethrins. They may be less toxic than some pesticides, but they are not without health and environmental concerns. Since there are nonchemical methods of control, it does not make sense to take a chance using something which is potentially harmful.

Bt or Bacillus thuringiensis is registered for use on sod webworm, and you can find it as well as beneficial insects, Steinernema nematodes from some gardening suppliers and well-stocked nurseries. Peaceful Valley Farm & Garden Supply has a large inventory of organic pest control products:

Natural Pest Control

Safer Caterpillar Attack

Parasitic Nematodes, Steinernema carpocapsae

Moth Egg Parasite - Trichogramma Wasp

I encourage you to pursue these alternatives to using the toxic product suggested by the maintenance contractor. Toxic chemicals can harm birds and beneficial insects, and using such products starts a vicious cycle, since those creatures would actually help keep down the undesirable webworm population.

Season All Season
Date 2007-10-03
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