Pest information courtesy of USFS Fact Sheets
Pests: The most common insect on Hackberry causes the
Hackberry nipple gall. A pouch or gall forms on the
lower leaf surface in response to feeding. There are
sprays available if you care to reduce this cosmetic
Scales of various types may be found on
Hackberry. These may be partially controlled with
horticultural oil sprays.
Diseases: Several fungi cause leaf spots on Hackberry. The
disease is worse during wet weather but chemical
controls are seldom needed.
Witches broom is caused by a mite and powdery
mildew. The main symptom is clusters of twigs
scattered throughout the tree crown. Prune out the
clusters of twigs when practical. It is most common
on Celtis occidentalis.
Powdery mildew may coat the leaves with white
powder. The leaves may be uniformly coated or only
Mistletoe is an effective colonizer of Hackberry,
which can kill a tree over a period of time. It appears
as evergreen masses several feet in diameter scattered
about the crown.
More on Tree Insects and Disease