Common name: Honeysuckle aphid
Scientific name: Hyadaphis tataricae
Hosts: Honeysuckle aphid feeds on many species of honeysuckle shrubs and vines, including amur honeysuckle (Lonicera maackii), Morrow’s honeysuckle (Lonicera morrowii) and tatarian honeysuckle (Lonicera tatarica). Tatarian honeysuckle is one of the most susceptible species used in landscapes. These species have fallen out of favor, due to their invasiveness, but many shrubs still remain in older landscapes and are found growing wild in native areas. While attacks from the honeysuckle aphid do not usually kill the plant, the production of witches’ brooms can decrease its overall health and greatly reduce its aesthetic value.
Feeding by the honeysuckle aphid leads to curled and dwarfed leaves. These early symptoms are typical of aphid damage. The insect’s salivary secretions cause the stunting of both leaf and stem growth. As the season progresses and more generations are born, the damage will involve several inches of the branch, resulting in small and weakened side shoots known as witches’ brooms. In autumn, the leaves on the witches’ brooms usually will turn brown and die before the shrub would normally produce its fall color. Often the damage done throughout the season does not become noticeable until winter when remnants of the dead foliage and the unsightly witches’ brooms are more apparent. While the damage done by the honeysuckle aphid is mostly aesthetic, the repeated production of witches’ brooms can diminish the host plant’s vitality, making it susceptible to other insects and diseases.
The entire life cycle of the honeysuckle aphid is completed on the host plant. As a non-migratory species, it overwinters as eggs on buds and branch tips of previously infested plants. In early spring, just as new leaves are emerging, these eggs hatch, bearing the first of several generations that will be produced continuously throughout the summer. Initially, only wingless females are produced without males (asexually). In late summer, winged males and wingless females are born, at which time they mate and deposit their eggs on the shrub. Generally, adult aphids remain inside the folded leaves where they are protected from weather and predators. In late summer, when the population of aphids can reach into the hundreds, they can be found outside the damaged, curled leaves feeding on petioles and stems.
The honeysuckle aphid can easily be missed during routine plant inspections. It grows to less than 1/16 inch in length and varies from a pale green to cream in color, with a fine, white waxy coating on its body.
Removing infested branches 6 inches below any witches’ brooms remaining from the previous season can be an effective method of control. Do this during the winter while the plant is dormant or in early spring before the eggs have hatched. This will not only remove the unsightly witches’ broom, but will also help reduce the severity of future attacks by eliminating most of the early season population. Any pruning done after the eggs have hatched may result in fresh leaf growth, which is then susceptible to further aphid damage. In general, cultural practices that encourage the production of new plant growth can intensify aphid problems. Plants that are Improperly pruned or over-fertilized with nitrogen often have the highest aphid populations.
Lady beetle adults and larvae will prey upon honeysuckle aphids. By late summer, many aphids will have been eaten by these natural predators. Winged aphids, however, can easily be blown in all summer to re-infest plants and deposit eggs for overwintering.
If insecticide sprays are used, they should be applied in the spring when the new leaves are developing and before the newly-hatched aphids begin their feeding cycle. Once the witches’ brooms are formed, the aphids are protected from insecticide sprays. For late season treatment, insecticides that can be drenched into the soil will be more effective. Drenches are more effective overall.
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For more information, contact The Morton Arboretum Plant Clinic (630-719-2424 or firstname.lastname@example.org).