Level Of Concern In Manitoba Maples

• Aphid Infestationants and aphids image by Undy from Fotolia.com
  
  Many different insects will attack maple trees in Manitoba. Most of these insects do not present a problem until they reach threshold levels. Home gardeners and tree farmers must monitor for insects and spray or treat only when the insects are present in sufficient quantities to impact the health of the tree. In most cases the visual appearance of aphids on Manitoba maple trees is much worse than the actual injury caused by the hungry aphids. Aphids feeding on succulent plant tissue often results in leaf curling and occasional shoot curling. Aphid feeding does not harm established maple trees, but will stunt the growth of young trees.
  
  

Aphids Cause Minor Damage

• In normal years, the box elder aphids cause only minor damage. The pear-shaped tiny insects are a real pest because they secrete huge amounts of honeydew. The honeydew cloaks the surface of the leaves with a sticky substance and presents a sooty, discolored appearance.
  
  

Natural Defense System

• In years of severe infestations, Manitoba maples are defoliated. The loss of foliage is especially evident in the fall when the maples are normally in full color. Although the Manitoba maple trees lose leaves, they are not dying. Resilient Manitoba maples have a natural defense system. When they lose their leaves from insect infestation or climate stress, they will manifest a new crop of leaves.
  
  

Lifecycle of Box Elder Aphids

• The lifecycle of box elder aphids is complex. In the early spring, eggs that have survived the winter develop into wingless females that are born pregnant. These pregnant aphids then give birth to up to a dozen new aphids daily. The new offspring are normally more pregnant females. In autumn, males are produced and the aphids mate, laying eggs which are dormant until the following spring.
  
  

Aphid Control

• Because box elder aphids reproduce so rapidly, spraying with chemical treatments is not efficient or practical. The best way to control these tiresome pests is to wash the tree with a garden hose. Water applied under pressure will remove the clumps of aphids from the leaves and help to control their spread to other trees.