Issue 11, July 11, 2016
We have been receiving reports of planthoppers in various areas of the state. The nymphs of these insects are covered with and leave behind white, fluffy tufts of waxy strands that get stuck on leaves and stems by the honeydew that these insects excrete. They are unlikely to cause enough damage to warrant control.
Planthoppers that are common in Illinois include Metcalfa pruinosa, Acanalonia conica, and Anormenis chloris. Nymphs of various species are found on many species of trees and shrubs, as well as some herbaceous perennials. They are probably most common on blackberry, rose, and hosta. They feed on plant sap with many species producing honeydew, plant sap that has had much of the water removed by the digestive system before being excreted. The feeding causes little apparent damage to the plant, although heavy feeding on hosta causes stunting and reduced bloom.
The nymphs hatch from eggs inserted into plant stems in the spring. They tend to feed in groups and are covered with white flocculent that probably reduces moisture loss and provides protection from predators. Mature nymphs molt into adults which fly away, leaving numerous strands of white flocculent behind. Being adhered to the plant by honeydew, it persists for several weeks.
Planthopper nymph on rose stem.
Adults are typically about one-quarter inch long and half as high. They sit on the stems, appearing like small leaves or flower petals. Metcalfa pruinosa is purplish as an adult, appearing somewhat like a dying, shriveled leaf. Acanalonia conica is green as an adult, appearing like a young leaf or leafy bract. Anormenis chloris is light green to white, appearing like young leaves or whitish flowers. They feed on sap as well. (Phil Nixon)