Diagnosing and treating the common garden pest euonymus scale can be tricky for a novice gardener. This is why it is so important to have a thorough understanding of what to look for and how to respond when euonymus scale is detected. The euonymus scale pest has a favorite list of plants that it regularly attacks, and infestations usually occur in the spring growing season. While the euonymus scale was first identified in the far East in Japan and China, it then made its way across the miles and has become a known issue in Europe and the United States for many deciduous and evergreen plants. Follow these tips from expert entomologists to successfully identify and treat euonymus scale before it destroys your garden.
While most deciduous and evergreen plants carry a mild risk of infestation by euonymus scale, English Ivy, Japanese Pachysandra, Wintercreeper Euonymus, American Bittersweet, Boxwood, Honeysuckle, Privet, Holly, Daphne, and most stone fruit-producing varietals like cherries and apricots are likely to become infected with euonymus scale.
The male and female of the euonymus scale species differ quite a bit in appearance. The male is twice as long as the female, and tend to appear in greater abundance than females when an infestation occurs. Males are long and narrow, white with a yellow tip at one end, and first appear to be tiny wasps when they emerge into adulthood. The female is grey-brown and pear-shaped, and rather flat when viewed from the side. Both the adult male and female of the species come equipped with an "armor," a waxy substance under which the adult insect shelters as it feeds off the growing plant.
The euonymus scale at adulthood is equipped with suckers that extract the intravenous juices from growing plants, literally sucking them dry like tiny vampires. As the infestation continues, foliage will start to appear yellowed and mottled, eventually dropping from the stems and branches until total defoliation has occurred.
Early detection is key in treating an euonymus scale infestation. Once euonymus scale attacks the base of the trunk or stem and gets into the root system, it becomes much more difficult to effectively stop an invasion. A natural solution that is gaining popularity in the Eastern United States is the introduction of the Lady Beetle, or Chilocurs kuwanae, which feeds on euonymus scale.
More commonly, euonymus scale is treated with application of commercial pesticide sprays, which must be repeatedly applied from May until August to deal with the double breed and hatch cycle of euonymus scale. It is very important to prune infected plants to remove all infested foliage, and to destroy heavily infested foliage to contain the infestation. In addition, spraying horticultural oil around the base of the infected plants can discourage growth of the larvae before they enter the "crawler" stage that is the prelude to adulthood and a new euonymus scale outbreak.
With these helpful tips and guidelines, you will be able to protect your garden from this pesky invasion.