Departments of Plant Pathology and Entomology
North Carolina Cooperative Extension Service
North Carolina State University

ORNAMENTALS
AND
TURF

North Carolina Pest News
Volume 11, Number 4, May 10, 1996
Stephen J. Toth, Jr. and Thomas A. Melton, editors

The information and recommendations in this newsletter are applicable to North Carolina
and may not apply in other areas.

From: James R. Baker, Extension Entomologist

Cool Weather Mites

Boxwood mites are a mystery: we often see the damage but rarely see the mites. Live boxwood mites were submitted from Gaston County, North Carolina by Stephen Greer, Agricultural Extension Agent. Although boxwood mites sometimes cause infested plants to be noticeably off-color, they do not usually cause general yellowing (or orange coloration) and dieback. Boxwood mites are also unusual in that they feed on the upper as well as lower surfaces of the leaves. Their feeding causes whitish spots to form on the leaf as they suck out the cell contents. Most mites feed here and there but boxwood spider mites tend to feed in a line so that the injured plant surface has tiny pale lines which resemble minute hen scratches. There are several generations per year but most of the injury seems to occur in the spring. Ornamentals and Turf Insect Note No. 53, the Boxwood Pest Control Calendar, lists pesticides available to manage boxwood mites.

The southern red mite is the most common spider mite pest of hollies and other broad leaved evergreens in the landscape. However, these pests usually do not cause dieback. It is one of the cool weather mites. Southern red mites do most of their damage in the spring and fall. They are relatively inactive in cold weather and often die out in bitterly cold weather (and very hot weather). Only the eggs survive these inclement periods. One of the horticultural oils should give adequate control of these mites. Ornamentals and Turf Insect Note No. 77 has additional information on the biology and control of these mites.

The most common spider mite pest of conifers in North Carolina is the spruce spider mite. The spruce spider mite is one of the cool weather mites. Spruce spider mites do most of their damage in spring and fall. Also, spruce spider mites tend to feed on the older growth. However, these mites usually do not cause dieback. Spruce spider mites are relatively inactive in very cold weather and tend to die out in hot weather. Because the spruce spider mite tends to feed on older growth, thorough coverage is necessary to get the pesticide inside the plant where the mites are feeding. This mite is not particularly resistant to miticides. Kelthane is the old standby for spider mite control. If that is unavailable, then one of the horticultural oils or Cygon will do the job. The horticultural oils are effective for spider mites and they also control armored scale insects. Cygon is also effective and has the advantage of being systemic.

Multi-colored Asian Lady Beetles

Remember those multi-colored Asian lady beetles that were driving people crazy last fall? This is the lady beetle that comes into houses in search of a dry place to spend the winter. During the spring and summer, harmonia lady beetles feed on aphids in gardens, meadows and trees. It probably will not do any good to remind people that these lady beetles and their offspring are now helping home gardeners by eating aphids in vegetable gardens, flowers, shrubs and trees. The immature stage of multi-colored Asian lady beetles are tiny, alligator-like insects that crawl about seeking aphids and other hapless insect to eat. The larvae are black with yellow splotches. Because lady beetles are attracted to plants that are infested with aphids and other plant pests, amateur horticulturists sometimes mistake this stage of the lady beetle life cycle for a damaging pest. Ornamentals and Turf Insect Note No. 74 explains more of the biology of lady beetles.

Spittlebugs on Pines

John Vining, County Extension Director, Polk County, North Carolina, reports that pine spittlebugs are fairly abundant in the county this spring. Pine spittlebugs overwinter in the egg stage. When the nymphs hatch from their eggs, they begin to feed. Spittlebugs suck sap out of the plants with their needle-like mouthparts. As the nymphs feed, they excrete spittle that protects them from predaceous mites and insects. Scotch pine often exhibits flagging of twigs at each pine spittlebug feeding site. The flagging is apparently caused by Diplodia pini, a fungus that invades the tree through the insect's feeding punctures. Similar localized dieback has been observed on Leyland cypress. Pine spittlebugs tend to be more abundant during dry seasons perhaps because dry weather inhibits the parasitic fungus, Entomophthora aphrophorae. On the other hand, high temperatures cause some mortality of the nymphs. There is only one generation per year. In July and August, female pine spittlebugs lay their eggs in dead wood or under the bark of live stems of pines, spruces, firs, hemlock and other conifers. I recommend that heavily infested Leyland cypress, junipers or pines be treated with lindane, Dursban, Decathlon, Orthene or some other contact insecticide now as spittle masses and spittlebugs are present or when the adults are present in early summer.

Web page last updated on 13 May 1996 by Stephen J. Toth, Jr..