Where do aphids deposit their eggs?

Holocyclic aphid species lay their winter eggs mostly in the crevices of their woody host plants. Common hosts are buckthorns, fruit trees, and rose bushes. These tiny black eggs are securely cemented to the bark by means of natural glues. They withstand freezing temperatures due to their protective coverings. I have found them in clusters under loosely adhering bark of the apple tree every winter.

Search for the eggs before spring with care. Look for bark cracks around the buckthorns and the fruit trees, using lenses or magnification. Note the branch union and the pruning wounds preferred by the females for laying eggs. Next, late in winter, the dormant oil sprays applied will smother the eggs. I have found, through experience, that this occurs about two weeks before the expected swelling of the buds.

Anholocyclic species are quite different. They entirely omit the egg stage, reproducing continually in the asexual state. The green peach aphid does not enter the egg stage, as it overwinters in the nymph stage, found on herbaceous plants or in greenhouses, thus causing continual infestations throughout the year in protected areas. Different methods are necessary to combat them, as controlling the eggs will not affect the others.

Effective management involves both monitoring and intervention. Survey host plants monthly in the fall, winter, and spring. Remove buckthorn from within 100 feet of gardens. Apply horticultural oils at 2% concentration before egg hatch. Introduce predators early to capture these emerging nymphs. Ongoing consistent efforts will help to reduce the chance of spring explosions.

Read the full article: Aphid Life Cycle: Stages and Secrets