Housed inside of the New Hanover County Arboretum is a plant clinic run by master gardener volunteers open Monday through Friday from 10 a.m. to 4 p.m. The clinic is open to the public and the volunteers assist with residential landscape problems. As you can imagine, similar problems show up in the clinic on a daily basis. Here are some of the ones we’re seeing now:
A few months ago we started to see a great deal of Eastern red cedar (Juniper) samples coming into the clinic experiencing rust galls that resemble an orange goop coming out of the stem of the cedar. Unfortunately, at this stage there is not a whole lot that can be done to manage the disease. During warm rainy spells gelatinous horn-like protrusions emerge from the gall. These fruiting bodies produced on the Juniper spread by wind and infect the alternating host — in this case a Bradford pear resulting in spots on fruit and twigs and less often on leaves. Later in the season fruit may be covered in orange-reddish spore horns, which will release spores to re-infect the junipers.
These reproductive structures can produce for several years and overwinter in gall tissues. Infected twigs often die.
Remove and destroy galls on cedar. This task is more difficult because of the less obvious shape and appearance of the gall. Often times when we observe the symptoms it is too late for control.
Remove the host to break the disease cycle. This strategy may not always work due to the ability of the spore to be spread over long distances. It is not recommended to plant junipers adjacent to rosaceous host. Fungal infections sometimes occur when junipers and members of the rose family such as apple, hawthorn and quince are grown in close proximity.
Make sure that all the infected fruit on your Bradford pear is removed as well as any fruit that has dropped to the ground. You will want to dispose of these in the trash and not in a compost pile.
This disease will not kill your Bradford pear but it will make it look unsightly. As the diseases begins to progress you may begin to see leaves around the infection turning a black color and it can often be confused with fireblight, which is a deadly disease if left untreated.
Fungicides may be used on hosts in the spring to protect it when spores are dispersed from the juniper host (when the yellow ‘goop’ appears on the junipers and are starting to dry). Fungicides containing the following active ingredients are commonly used to manage this disease: Mancozeb, Chlorothalonil, Myclobutanil, and Propiconazole.
Have you noticed a fuzzy white powder covering the upper stems of hosta, azalea and many other landscape plants that looks like a fungus?
Try this experiment. Use a pine needle to poke the white fuzz on your plant. Surprise! Perhaps half a dozen white insects will suddenly hop off the stem in all directions. If you touch the white powder with your fingers, it will seem sticky. The white insects are juvenile planthoppers. While feeding on your plant, they excrete filaments of white wax in order to protect themselves from predators.
Planthoppers do little damage to their host plants. The female inserts her eggs into plant stems and the nymphs feed on young leaves but little injury is ever noted. If the appearance of planthoppers is objectionable on your plants, no insecticide is recommended. Just blast them away with a water hose and give a nearby spider or beetle a good meal.
Symptoms and diagnosis
Hoppers are agile insects that can move with equal ease either forwards, backwards, or sideways like a crab. The crab-like motion distinguishes hoppers from most other insects. In addition, they can hop to escape danger or to move to another host plant.
For answers to your gardening questions, visit ces.ncsu.edu where you can submit questions via the ‘Ask an Expert’ link, or contact your local Cooperative Extension center: in Pender County, call 910-259-1238; in New Hanover County, call 910-798-7660; in Brunswick County call 910-253-2610.
Susan Brown is the consumer horticulture agent with the N.C. Cooperative Extension’s New Hanover County center.