Spraying Sequoia Birch tree
I have sprayed my Birch tree previously using a mixture of Dawn and water and it seems to help with the aphid problem that causes the leaves to die later in the summer. I cannot remember the mixture--i.e. someone says half and half which seems to be a bit extreme. Will this mixture also work on evergreens?
Coos County Oregon
Thank you for your question. Although soaps are one less toxic method to use on aphid control, using the correct soap is also necessary, and will 'work' on a variety of plants, but the mixture has to reach the aphids and smother them. This is less effective on large or complex trees, since you simply can't reach all the places they may be hiding. Here is an OSU article that suggests the most effective, organic methods of aphid control: https://extension.oregonstate.edu/news/how-control-aphids-less-toxic-methods
Hope this is helpful. Good luck!