Is the firebug a pest?

The firebug (red and black, in clusters on lime trunks in spring) is not a pest: it eats the seeds of the mallow family (lime, mallow) and dead insects, and barely harms plants, so leave it be. It gets confused with the cabbage (harlequin) bug: smaller, also red and black, but sitting on cabbage, radish, mustard and horseradish, and it really does suck the leaves. Against that one: fleece over young cabbages, watering in hot spells, picking by hand, and no brassica green manures nearby.