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Scale • 7% of all street trees are affected by scale Scales are small insects that suck the sap out of trees, reducing the tree’s resources. Freeman and red maples are affected by gloomy scale, which was observed in more than 80% of Freeman and 35% of red ma-
RECOMMENDATION: Reduce planting of willow oaks and maples
immediately and attempt to control these pests with insecticides. This can only be done at certain times of the year when the scale’s lifecycle allows.
ples. Additionally, a different type of scale (lecanium) was observed in willow oaks in Heritage and it is known to occur in Olde Mill Stream as well. Given the large amount of value in maples and willow oaks, the impacts of scale could be severe if untreated.
Defoliators • 14% are affected by defoliating insects
Ornamental cherries were heavily attacked by leaf eating insects, which is common for mem- bers of the rose family. American elms also show signs of insect damage. Some red oaks were entirely defoliated by orange striped oakworm. However, these can be treated easily, and even full defoliation should not kill the tree unless repeated annually.
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Common Pests and Diseases
Gloomy scale on a red maple. These armored insects reduce the tree’s energy, making it more vulnerable to environmental conditions, pests, and diseases.
Severe defoliation by orange striped oakworm
Cristulariella leaf spots on a sycamore leaf
RECOMMENDATION: Inspect oaks for oakworm outbreaks, particularly where the trees were defoliated in previous years, and treat as necessary. Monitor American elms, and provide routine maintenance as needed.
Minor defoliation on an ornamental cherry tree
Leaf spots on water oak, a member of the red oak group
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