There have been reports of excessive “honeydew”
from trees in the area. Honeydew is the sticky sap that falls under trees,
usually onto pavement, grass, vehicles and ornamental plants. This
inconvenience is caused by aphids. You will be able to find the aphids by
looking for tiny pear-shaped insects on the underside of the leaf. They are
very small, about the size of a poppy seed or some of the larger species are the
size of a sesame seed. They range in color from light green to nearly black.
They have many generations per year so populations increase rapidly. Some
generations of aphids will develop wings to travel to their next location.
Each aphid species will attack a specific species of plant
and will not attack other species. For example, Elm tree aphids will not attack
garden crops. Damage caused by aphids is seldom fatal to a tree because trees
produce more leaf area than they need, but in the case of our trees, can make a
sticky inconvenient mess.
You may have also noticed a few more ants around the sappy
tree. The ants protect the aphids from their natural enemies and in turn eat
the honeydew produced by the aphids. Placing a barrier around the plant or tree
such as a sticky material like Tanglefoot, can keep ants out of trees and
shrubs, allowing beneficial insects to attack the aphids.
Montana State University Entomologist, Will Lanier comments
“Aphids damage a tree from the leaves out and will not permanently damage the
tree. Hosing the tree with a strong stream of water will help. Using
horticulture soaps and oils, excluding ants and using chemicals containing
pyrethrins are also additional least toxic controls. Lady Bird beetles should
be allowed because they are a natural control of the aphid. Remember all trees
produce a lot more leaf area than they need to survive so some damage is more
acceptable than chemical control.”
For more information on aphids or other insect problems,
visit http://scarab.msu.montana.edu/extension/ or call the Roosevelt County
Extension Office at 787-5312. |
