Severe Scale Infestation on Holly Tree - Ask Extension
What treatment, if any, do you recommend for what looks like cottony camellia scale on our holly tree? The infestation is severe, affecting almost all...
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Severe Scale Infestation on Holly Tree #641203
Asked May 26, 2020, 1:26 PM EDT
What treatment, if any, do you recommend for what looks like cottony camellia scale on our holly tree? The infestation is severe, affecting almost all of the old growth. I only noticed this in spring, once dormancy was past. Will a summer application of neem oil or horticultural oil help? This tree was here when we bought the house 32 years ago and I would hate to lose it.
Baltimore County Maryland
Expert Response
Yes, this is cottony camellia scale. This has been a big year for it as we have had many similar questions. It is worth trying to treat it if you can as your holly is pretty tall.
We recommend using horticulture oil.
Here is our page about cottony camellia scale and recommendations for management, https://extension.umd.edu/hgic/topics/cottony-camellia-scale-shrubs
You can apply a horticultural oil spray (at the summer rate, 2%) now. You can find horticultural oil in garden centers or the garden section of some hardware stores. Read and follow the product label instructions.
Scale insects are notoriously difficult to control. If the problem persists, you can treat again with horticultural oil in the dormant season (after the leaves have fallen from deciduous trees). Pruning out some of the heavily damaged portions of the shrub is also okay.
Deb
We recommend using horticulture oil.
Here is our page about cottony camellia scale and recommendations for management, https://extension.umd.edu/hgic/topics/cottony-camellia-scale-shrubs
You can apply a horticultural oil spray (at the summer rate, 2%) now. You can find horticultural oil in garden centers or the garden section of some hardware stores. Read and follow the product label instructions.
Scale insects are notoriously difficult to control. If the problem persists, you can treat again with horticultural oil in the dormant season (after the leaves have fallen from deciduous trees). Pruning out some of the heavily damaged portions of the shrub is also okay.
Deb
