Insects:
Calico scale
Calico scale is a pest of fruit trees, maples, crabapple, elm, dogwood, and honeylocust. The adult female is 1/4" with black and while patches. Calico scale is a soft scale. Soft scale adults usually attach to twigs and branches while immatures feed on leaves. In addition soft scale are known for these characteristics: feed on phloem sap (adults may be found near pruning wounds); produce large amounts of honeydew; swell when eggs are nearing emergence; and release 100's of eggs. One generation occurs per year with the color darkening with age. Crawlers emerge from the darker colored females.

Double-sided tape wrapped around the truck or branches can be used to scout for scale crawlers. Another method is to tap branches over a piece of white paper. The crawlers will appear to be moving specks of dust. Identifying when the crawlers are present is important to effectively time sprays.

Horticultural spray oils kill all stages of scales that are present at the time of application, and often give good control. Summer oil sprays must be carefully applied to avoid injury on some species. Because of their waxy protective covering, stages of scale other than the crawler are not readily controlled by contact insecticides. Chlorpyrifos, Malathion, Orthene (acephate) and Sevin (carbaryl) are registered for scale control.

Leafhoppers
Several leafhopper species affect woody plants. Recently leafhoppers were on elms and honeylocust and their feeding damage resulting in stipling of the leaves. Potato leafhopper, the species that affects maples, causes curled leaves, hopperburn, stunted shoots and can affect winter hardiness. Action thresholds indicate that potato leafhoppers should be controlled on maples when there are an average of 3 leafhoppers per branch, on an average of 4 branches per plant in order to avoid cupping and curling leaves.

Researchers have found that Acer x freemanii ‘Indian Summer' is tolerant to potato leafhopper.

Source: Environmental Entomology 2001, vol. 30, no. 3, pp. 533 - 539; Purdue Pub. E - 213, Developing an Integrated Pest Management Program for Nurseries

Shoot Boring Caterpillar
Shoot boring caterpillar has struck; it is too late to spray and reduce damage. See Nursery Update #12 for more information about this pest.

Cultural:

Pruning
Some growers prune dogwoods now in order to develop full canopies. Shears, which are usually reserved for pruning hedges, are used. Because the removal of foliage can be stressful, pruning is likely useful only on dogwoods that are established and pest free (powdery mildew and dogwood borer), meaning they are healthy and vigorous enough to respond to the pruning cuts with new branch development. The advantage to using shears to prune the canopy is speed. The negative impact of this technique is that stubs, such as those shown in the image, are left behind when too large of a stem is cut. Stubs can be entry sites to diseases and insects and can be unsightly. Whether you choose to use shears or not, pruning now can lead to denser canopies later.