EDIT (March 2018): the following advice works, I believe. I observe plague proportions of these bugs destroying fruit in nearby gardens, while my yard has only a few of them wandering around without causing much problem. I mention removing mallow weeds; I’d remove all tall weed patches around the garden, and if you border on a vacant lot, maybe a strip along the side of it as well. Living weeds and tall grass seem to provide vital harbour even when they aren’t also food.
With a brief moment of warm weather on September 2 this year, the harlequin bugs are on the march again.
Many gardeners around Bacchus Marsh have encountered plagues of these sap-sucking critters. They are remarkably adaptable, feeding off hosts as widespread as mallow, pepper tree, citrus, tomatoes and rhubarb. Most insects that are leaf-chewers only feed off one or a few closely related species of plant, because they need to specialise their metabolism to overcome the chemical defenses of the plant. Sap-suckers bypass the leaf with its battery of noxious compounds, and tap straight into the sweet flow of the plant’s sap, which is relatively free of chemical defenses. Continue reading