By Whitney Cranshaw, Colorado State University Cooperative Extension specialist, entomology
Since its entry into Colorado in the early 1980s, the honeysuckle witches broom aphid has been a recurring and serious pest of ornamental honeysuckle. Feeding by these aphids causes new growth to curl and discolor. Dormant side shoots form in response to the injury which, in turn, also become infested. The result is dense, matted "witches broom" growth the often dies during winter. Most bush type (tatarian) honeysuckle cultivars are susceptible to this insect, although vining honeysuckle is immune. Honeysuckle is the only host of the insect.
Perhaps because it is an introduced, exotic insect, few natural enemies effectively control populations of this insect. You can remove overwintering stage eggs by pruning the older damaged terminals, but reinfestation often is rapid. By carefully examining new growth for evidence of curled, distorted leaves, incipient problems can be removed if you cut out infested terminals. The most effective means of controlling the honeysuckle witches broom aphid is by using insecticides that move systemically in the plant, such as acephate. Read the label to identify this product. Because the aphids are largely protected within tightly curled leaves, most other insecticides, which work by contact action, provide poor control.
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010