treating cottony maple scale on thornless hawthorne - Ask Extension
Hello,
Our thornless hawthorne is showing leaf scorch and what we think is cottony maple scale. Wondering if there's anything we can treat it with ou...
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treating cottony maple scale on thornless hawthorne #873023
Asked June 13, 2024, 5:28 PM EDT
Hello,
Our thornless hawthorne is showing leaf scorch and what we think is cottony maple scale. Wondering if there's anything we can treat it with ourselves? (horticultural oil?) It's a small tree. Also, we've just had a local tree place out to treat our very bug infested honey locusts. ($$). Thanks!!
Larimer County Colorado
Expert Response
Hi Janice,
Actually, this is hawthorn mealybug and (unfortunately) a common insect of hawthorn trees. The brown tips are likely linked to a cold snap we had when the tree was leafing out - this happens often as some trees break dormancy.
Mealybug can be difficult to control - if you've ever had it on houseplants, it's the same insect, but just a different species.
An effective control would be to wait until the "crawlers" emerge in the fall and then use a horticultural oil to smother them. The crawlers overwinter on twigs and in bark cracks. You could also do a late winter dormant oil to do additional control.
This is explained in better details in our publication: https://webdoc.agsci.colostate.edu/bspm/Hexapoda%20(Insects)/Hawthorn%20Mealybug%20December%202014%20Revision.pdf
Did you honeylocust have plant bug? https://extension.umn.edu/yard-and-garden-insects/honeylocust-plant-bugs
Actually, this is hawthorn mealybug and (unfortunately) a common insect of hawthorn trees. The brown tips are likely linked to a cold snap we had when the tree was leafing out - this happens often as some trees break dormancy.
Mealybug can be difficult to control - if you've ever had it on houseplants, it's the same insect, but just a different species.
An effective control would be to wait until the "crawlers" emerge in the fall and then use a horticultural oil to smother them. The crawlers overwinter on twigs and in bark cracks. You could also do a late winter dormant oil to do additional control.
This is explained in better details in our publication: https://webdoc.agsci.colostate.edu/bspm/Hexapoda%20(Insects)/Hawthorn%20Mealybug%20December%202014%20Revision.pdf
Did you honeylocust have plant bug? https://extension.umn.edu/yard-and-garden-insects/honeylocust-plant-bugs
Dear Dr. O'Connor,
We greatly appreciate your help with our tree issues. We will wait until fall/dormant season to spray our Hawthorne. Also appreciated the article on Honey Locust bugs. That infestation was something else.
We so appreciate the help of the Extension and its Master Gardeners. We're sort of newbies at all of this and you help us find our way.
Janice & Bruce Long
Loveland
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