Beauty and the Insects | Daily

“The commercial landscapers and industry professionals are now very familiar with the scales of myrtle bark,” Wootten said. “Cooperative Extension has highlighted myrtle bark scale in our workshops and continuing education since it was discovered here in 2020.”

So what should you do if you suspect there is myrtle bark on your tree?

“Myrtle bark scales are not harmful to the overall health of the trees and may not require treatment,” Kunkel said. “Natural predators, ladybugs and lacewings often keep populations suppressed.”

Indiscriminate spraying of trees can kill the bark scales’ natural enemies, often without damaging the scales. Kunkel advises against the use of neonicotinoid pesticides. Although neonicotinoids are effective against myrtle bark scale, these insecticides can contribute to the decline of pollinator populations.

“Then you’ve created an enemy-free space, which means there’s nothing to eat the scales, and their populations will explode,” Kunkel said. “However, treatment can preserve the beauty of your tree. If left unchecked, myrtle bark scales can reduce flowering. Honeydew covers the trunk and branches, which are quickly colonized by unsightly black sooty mold.”

Small clumps of myrtle bark can easily be crushed or scraped from the tree. Empty scales remain on the tree even after the insects have died, so it can be difficult to measure the extent of active infestation.

So if you see these invasive insects on a tree near you, don’t worry. Delawareans can contact the UD Cooperative Extension garden helpline. This free resource is available year-round and provides help on a variety of gardening topics.

Help UD monitor the movement of this insect in New Castle County. To report possible sightings of myrtle bark scales, please call the New Castle County Master Gardeners at 302-831-8862.

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