This year, the giant conifer aphid has been found on spruce and fir trees. Most years this aphid is not a problem. It is amazing how quickly aphids can reproduce. If weather conditions are right, they can pass through one generation in less than two weeks. When aphids become overpopulated, they can produce a winged generation that flies off to a new area.
Aphids prefer moderate temperatures with a little bit of moisture.
Hot summers can retard their growth and damage. When aphids feed, they produce honeydew, a substance that can become so thick it drips from trees and plants onto cars, picnic tables, people and slow-moving pets. Honeydew is just a sugar-water substance and is not toxic to plants or the people it drips on. Aphids suck and feed on the sap of their host. If left unchecked, the leaves they feed on begin to curl, providing the little pests a nice protected area where they can continue to feed uninterrupted.