Spraying Douglas Firs: toxin question

Asked May 7, 2015, 8:16 AM EDT

Hello, Our neighborhood in State College has a fungus problem with Douglas Firs. A local tree service (http://www.aikeystreeservice.com/) is treating our trees with Chlorothalinol and Cupro 5000. In the below 2 reports, the first report has caused concerns and questions, as we have gardens, fruit trees, and many children playing in our yards. Although the 2nd report appears to identify that use of these toxins should not alarm us, can you speak to these fungicides and whether we should be concerned? Because we've been told by the tree service that they need to apply 3 treatments this spring-summer, we'd like to know what level of precautions we need to take. Today, we've covered a neighbor's unplanted garden and a berry bush. However, we did not cover nearby fruit trees. What type of concern should we have? Thanks you very much! 1. http://pmep.cce.cornell.edu/profiles/extoxnet/carbaryl-dicrotophos/chlorothalonil-ext.html 2. http://www.agf.gov.bc.ca/pesticides/infosheets/chlorothalonil.pdf

Centre County Pennsylvania fungus douglas fir horticulture

1 Response

I'm going to refer you to a fact sheet published by the University of California Davis.

Environmental Fate and Toxicology of Chlorothalonil
According to the fact sheet, it's effect on people seems to be uneven depending on whether or not they develop a sensitivity to the molecule. One of the things I noticed is that it persists in the soil for a rather long time.
Cupro is a copper product, and forms of copper are used in organic gardens as well as traditional gardens. The fact sheet I linked explains how the copper acts to control fungus.
Since your Douglas Firs are valuable and you need to control the fungus to save the trees, a qualified tree service with a license to use these products would know how to handle them properly.
If you want more in-depth information, I would contact your local Penn State Extension and ask them to recommend someone at Penn State that is knowledgeable in this area, someone in diseases of woody ornamentals or pest management perhaps.