aspen blight - Ask Extension
Our aspen trees seem to have developed a blight of some kind. They look fine in spring and summer but in the fall they develop brown spots on them. No...
Knowledgebase
aspen blight #149885
Asked August 28, 2013, 7:12 PM EDT
Our aspen trees seem to have developed a blight of some kind. They look fine in spring and summer but in the fall they develop brown spots on them. Now they also have a milky-looking white developing at the juncture of the leaf and the stem, plus tiny black bugs on them. (please see attached jpgs). What can we use on our trees to kill the blight and prevent this from spreading? Thank you.
Laraine N., Estes Park, CO.
Laraine N., Estes Park, CO.
Larimer County Colorado
Expert Response
Hello,
The insects are really difficult to identify from your picture, but it appears as though there might be aphids (notice any sticky substance?) and black insects may be natural predators.
As for the while film, it looks like powdery mildew, a common disease this time of year, which doesn't affect the leaf.
Really, at this point in the season, it's not worth applying any fungicides or insecticides to treat these problems. You're better off raking the leaves as they fall in the fall and disposing them in the trash, so as not to continue the infection cycle next summer.
Also, be sure to give the plants proper TLC, including fall and winter watering. If you want someone to look at your trees, Larimer County Extension does have a Tree Team service, where Master Gardeners visit your property and can make assessments. The fee for this service is $25/hour. If you're interested, please email me directly at: <personal data hidden>
Thank you!
The insects are really difficult to identify from your picture, but it appears as though there might be aphids (notice any sticky substance?) and black insects may be natural predators.
As for the while film, it looks like powdery mildew, a common disease this time of year, which doesn't affect the leaf.
Really, at this point in the season, it's not worth applying any fungicides or insecticides to treat these problems. You're better off raking the leaves as they fall in the fall and disposing them in the trash, so as not to continue the infection cycle next summer.
Also, be sure to give the plants proper TLC, including fall and winter watering. If you want someone to look at your trees, Larimer County Extension does have a Tree Team service, where Master Gardeners visit your property and can make assessments. The fee for this service is $25/hour. If you're interested, please email me directly at: <personal data hidden>
Thank you!
