They are sometimes referred to as Fall migrants. These individuals produce females which mate with males of the previous generation. These mated females lay eggs that overwinter. Most aphids cause damage to host plants by robbing them of plant fluid, by the toxic action of their salivary secretions injected during feeding, and by serving as vectors of viruses that are harmful to plants. Feeding by Aphids can stunt plant growth, deform leaves and fruit, or cause galls on leaves, stems and even roots.
Many Aphids also excrete a sticky, sugar-containing substance known as honeydew.
This material will drop onto the leaves, twigs, and fruit of a plant. A black, sooty mold soon begins to grow on this sugar-rich substrate. This mold not only mars the appearance of the plant, but when abundant, will also reduce the food-making process of a plant known as photosynthesis. Honey dew is attractive to ants, flies, hornets, and yellowjackets. It can also mar cars, chairs, tables or other objects that are beneath Aphid-infested plants.