Plant Bugs Damaging Elderberry Plants

Published: May 31, 2017

In April, damaged elderberry plants were observed in field plantings at several Missouri locations. Symptoms were dead or damaged terminal growing points of young succulent shoots or recurved leaflets with necrotic margins on new tissue (Figure 1). Where growing points were killed, lateral buds eventually grew, however, the cyme that would have developed from the damaged tissue will not be produced. In cases where the leaflet margins were damaged, this tissue fails to enlarge, but subsequent "normal" growth occurring from the growing point resumes. Upon close inspection, a 2 mm-long insect was found feeding on the plant tissue, which has been tentatively identified as a nymph of Neurocolpus jessiae (Figure 2). Early nymphal stages (instars) of this insect have green bodies covered with dorsal brown setae (hairs) and a dark spot at about two-thirds of the length of its body. It also has long antennae with three alternating brown and green segments covered with setae. Legs of nymphs are similarly long with alternating brown and green patches with relatively long, erect setae.

Figure 1 Necrotic growing point and leaflet margins damaged from plant bug feeding.

Figure 2 Early stage plant bug nymph (with legs folded and obscured by the abdomen) found feeding on succulent new growth of elderberry plants.

Figure 3 Adult plant bug (tentatively identified as Neurocolpus jessiae ) observed on greenhouse-grown 'Bob Gordon' American elderberry plants.

Neurocolpus jessiae is classified as a true plant bug in the Family Miridae. This species was collected by Jessie Knight at Hollister, Missouri on July 3, 1921. Later descriptions state that there are two generations, with the first occurring in early summer in June and the second one in August. Other researchers report that Neurocolpus jessiae adults feed on elderberry flowers and berries, reducing berry production. Additionally, adults have been found on nearby flowering plants, including hollyhocks (Alcea rosea) and Viburnum species. Since this plant bug was first identified, it has been collected across the eastern United States where elderberry is found, including Iowa, Illinois, Mississippi, Texas, Massachusetts, Wisconsin, and Ontario, Canada. While Neurocolpus jessiae apparently feeds on vegetative tissues, flowers, and berries of elderberry, the damage to plant growth and crop yield has not yet been documented. For products approved to control plant bugs in Missouri, see: http://www.kellysolutions.com/MO.