Shield bugs, also known as stink bugs and green vegetable bugs, are common in gardens where they invade plants and use their hypodermic like mouth parts to suck sap. As their stink name suggests they have a powerful unpleasant odour when squashed.
Identify the problem
Shield bugs (including stink bugs and green vegetable bugs) are sometimes mistaken for beetles, but they belong to the group of true bugs, the Hemiptera. The shield bug name comes from the shield shaped flat body shape, stink bug name comes from their smell and green vegetable bug comes from the fact that they are often found on ...green vegetables.
Shield bugs feed by sucking sap from a wide range of plants but generally the green shield bug causes little noticeable damage to cultivated plants, unless there are many bugs.
Shield bugs are active in early summer when they lay small clusters of eggs on the undersides of leaves. In late summer and autumn they are often seen sitting on plant foliage in the sun. Shield bugs survive winter as adults.
Note: The Brown Marmorated Stink Bug (BMSB) is an agricultural pest found in many asian countries. It has invaded the USA and could successfully establish in New Zealand. It can feed on a wide variety of plants causing damage and will also invade homes in significant numbers. See here for more details on how to identify BMSB. Any possible sightings should be reported to MPI Biosecurity on 0800 80 99 66.
To get rid of shield bugs:
- Shield bugs (stink bugs or green vegetable bugs) are difficult to control.
- PLANThealth Spectrum and Organic Insect Control have little effect unless sprayed directly on the insects. But they will help protect treated plants as the shield bugs move from plant to plant.
- There is some evidence that squashing one shield bug/stink bug/green vegetable bug releases the pungent odour and that it deters other stink bugs.
Did You Know
- The immature nymphs have a rounded body shape and gradually take on the adult appearance as they develop.
- In recent years the green shield bug has become more abundant and widespread in New Zealand.
- There are species of shield bugs, which are green brown or yellowish green with reddish markings, that can also be found in gardens.
Common species include:
- New Zealand Shield bug - Glaucias amyoti
- Green vegetable bug - Nezara viridula