The British call these soft-bodied pests “plant lice,” a sign of how ubiquitous they are in gardens. Often the color of their host plant, they suck juices from tender leaves and stems, distorting them and weakening the plant. More often than not, aphids are aided and abetted by ants that “farm” (tend and protect) them for the honeydew they secrete. Fortunately non-chemical controls are remarkably effective. Start by dislodging the bugs with a blast of water or flick of the finger. (The non-squeamish can squash them between their fingers for instant gratification.) Then control ants using “ant motels” that let foraging ants take pesticide home to ultimately destroy the hill. If aphids are in citrus and other trees, a trunk barrier like Tanglefoot spread on a protective collar can help keep ants out of the tree. Avoid the use of broad-spectrum pesticides since aphids have plenty of natural enemies that could be wiped out as well. More information is at www.ipm.ucdavis.edu.