by Ann Barnes
For the past few weeks I have been battling some distinctive bugs for control of the kale.
This is the Harlequin bug (Murgantia histrionica), a type of stink bug that feeds on many cole crops, including kale, collards, cabbage, broccoli and brussels sprouts. If these preferred crops aren’t present, Harlequin bugs also feed on tomatoes, potatoes, asparagus, squash, and even fruits. Harlequin bugs feed by piercing leaves and sucking, leaving white to brown damaged spots. Wilting and death of the plant can occur in severe infestations.
The eggs of Harlequin bugs are as notable as the adults. Eggs are laid in rows of 6 on the undersides of leaves and are black and white striped. Nymphs are as brightly colored as the adults. Their striking coloration make Harlequin bugs easy to spot under leaves. In a small garden like mine, they can be controlled by removing eggs and bugs by hand. Knocking the adults and nymphs into a small bowl of soapy water is easy and doesn’t require too much direct contact with potentially bad-smelling adults.
This video shows leaf damage caused by Harlequin bugs:
Adults overwinter in plant debris and in weedy areas around gardens. Removing weeds and the previous season’s crops can reduce populations. As always, crop rotation is recommended. There are some resistant plant varieties available (see this publication).
In addition to hand-picking insects from plants, nymphs can be controlled with insecticidal soaps or pyrethrins if necessary. A heavily infested plant can be used as a “trap crop” – remove and destroy the plant along with the pests.