Seeking pollinator-friendly treatments to control oystershell scale on an ash tree - Ask Extension
An ash tree on my property east of Colorado Springs has had oystershell scale for a number of years. In the past, I have used root-applied systemic ...
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Seeking pollinator-friendly treatments to control oystershell scale on an ash tree #862506
Asked March 25, 2024, 8:15 PM EDT
An ash tree on my property east of Colorado Springs has had oystershell scale for a number of years. In the past, I have used root-applied systemic neonics, recommended by an arborist. However, I am hosting a bee hive for a local beekeeper and am looking for ways to help the tree without harming the bees.
Do you have any suggestions?
El Paso County Colorado
Expert Response
Hello
There are a variety of ways to control oystershell scale. If you can time it right, the best time to spray is during the crawler stage, when they are the most vulnerable. However, this involves using crawler sprays, which might affect the bees, even though it is sprayed on the bark, and doesn't get into the flowers.
You could try a summer oil spray- this is an oil that is sprayed in June, when the scale insects have minimal wax cover, and they can be smothered by the oil.
You can read more about the life cycle and some options in this fact sheet:
https://extension.colostate.edu/topic-areas/insects/oystershell-scale-5-513/
and more about horticultural oils here:
https://extension.colostate.edu/topic-areas/insects/insect-control-horticultural-oils-5-569/
There are a variety of ways to control oystershell scale. If you can time it right, the best time to spray is during the crawler stage, when they are the most vulnerable. However, this involves using crawler sprays, which might affect the bees, even though it is sprayed on the bark, and doesn't get into the flowers.
You could try a summer oil spray- this is an oil that is sprayed in June, when the scale insects have minimal wax cover, and they can be smothered by the oil.
You can read more about the life cycle and some options in this fact sheet:
https://extension.colostate.edu/topic-areas/insects/oystershell-scale-5-513/
and more about horticultural oils here:
https://extension.colostate.edu/topic-areas/insects/insect-control-horticultural-oils-5-569/
