Harlequin Bug

A shield-shaped stink bug in loud black and orange-red, about a third of an inch long, that feeds on cabbage-family plants. It sucks sap and leaves white or yellow pinprick spots that spread until the leaf looks bleached and tattered.

Pest13 plants we cover get harlequin bugmostly annuals

Pest checklist

Four things to look for. If most of them match what you are holding, you are in the right place.

Bold black-and-orange shield-shaped bugs sitting in pairs on the leaves
Eggs like tiny black-and-white striped barrels standing upright in double rows under a leaf
Round black nymphs with red and yellow markings, too small to have wings
Pale stippled spots that run together into bleached, wilting leaf edges

What gets rid of them

Gentlest option first. For most backyard cases the first one is enough, so try these in order and stop as soon as it works. If you do spray something, the product label tells you how — please read the notice further down.

1Hand-pick and crush eggs
Turn leaves over every few days and knock bugs into soapy water, then scrape off the striped barrel eggs.
Try this first
2Clear out the debris
Pull old brassica stumps and wild mustard weeds at the end of the season, since the adults spend the winter in that litter.
3Cover fall greens
Put insect netting or row cover over fall brassicas at transplanting so the adults cannot reach them.
insect netting garden row cover
4Plant a trap row of cleome
Grow a few cleome plants at the edge of the bed; harlequin bugs prefer them, and you can pull and destroy the trap plants once they are loaded.
cleome spider flower seeds

As an Amazon Associate, Story Thyme Farms earns from qualifying purchases, at no cost to you. It never changes what we recommend.

Which plants get harlequin bug

Every plant we cover that gets harlequin bug, grouped by type — tap any one to open its page. A note beside a plant came from that plant’s own entry, because the same pest can be a minor nuisance on one plant and a serious problem on another. Plenty of plants we do not cover get it too.

annuals13

Plant families hit hardest

Related plants often share the same problems, so if one plant in a family has it, check the others. The largest group here is Brassicaceae, with 12 of the 13 affected plants.

Brassicaceae12 plants

When to treat

Hand-pick and crush eggs from the moment you see the first adults in spring, because a fall brassica planting can be ruined in a couple of weeks once a colony builds up.

On specific plants

Collard Greens
Growing
Bt program; harlequin bugs hand-picked in fall.

Timing only — the label is the law

This page tells you when to watch for harlequin bug and when treating is worth considering. It is not a recommendation to apply any particular product. Read and follow the product label before you spray — under federal law the label is the legal instruction, and using a pesticide against it is illegal.

Check the pre-harvest interval. Every product that’s cleared for an edible crop sets a minimum number of days between spraying and picking. Find it on the label before you spray anything you intend to eat.
Check the re-entry interval before you or anyone else works in the treated area again, and use the protective equipment the label names.
Confirm the product is registered for your crop in your state. This page groups many different crops together, and a product legal on one of them is not legal on all of them — state registrations differ too. Your state pesticide agency or local extension office can confirm both.
Rates and mixing instructions come from the label, never from us. We don’t publish them because they differ by product and formulation.