Fourlined Plant Bug

Adult fourlined plant bug.

Description of fourlined plant bugs

Fourlined plant bug is well named. It is an attractive insect with 4 black stripes separated by three bright yellow stripes. The adult insect is slightly longer than 1/4 inch.

Life cycle of fourlined plant bugs

Fourlined plant bugs are not picky eaters and will feed on sap from over 250 different kinds of plants. Their piercing-sucking mouthparts puncture the leaves and sap is sucked from the tissue. The immatures (nymphs) feed from late April to late June, and adults are present the remainder of the summer, though they only feed until approximately mid July. The adults lay eggs in the fall, and when the eggs hatch the following spring, the cycle starts over. There is only one generation per summer.

Fourlined plant bug feeding damage on mint.  Damage is often mistaken for a leaf-spot disease.

Damage caused by fourlined plant bugs

The points where the bugs puncture the leaves show damage symptoms characteristic of this insect. Damage typically appears as a black or translucent spot, usually surrounded with a halo of different color. Injured areas may drop out of the leaf, leaving small holes.

Management of fourlined plant bugs

Because fourlined plant bug is not a common pest in Iowa, we do not anticipate the damage and begin protective sprays in May when they would be of significant benefit. Late sprays applied after the damage becomes apparent and after the nymphs are grown are of no benefit. Since we are now at that point in the year, diagnosis of fourlined plant bug injury should not lead to spraying but rather to watering, pruning and other 'TLC' measures that promote plant health and recovery.

The visible red abdomen of fourlined plant bug  nymphs.

Do you live in Iowa and have an insect you would like identified?

The Iowa State University Plant & Insect Diagnostic Clinic will identify your insect, provide information on what it eats, life cycle, and if it is a pest the best ways to manage them.  Please see our website for current forms, fees, and instructions on preserving and mailing insects.   

Contact information for each states diagnostic laboratory for U.S. residents.  If you live outside of Iowa please do not submit a sample without contacting the Plant & Insect Diagnostic Clinic.  


Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Yard and Garden, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on September 12, 2016. The information contained within may not be the most current and accurate depending on when it is accessed.