Prickly Pear Cactus & Green Insect Pests

Growing Conditions

• Plant the prickly pear cactus in a light, nutrient-rich, well-drained soil. Water-logged soils are the No. 1 cause of prickly pear problems, and when the cactus is sick, it attracts more pests. Opuntia cacti prefer warm, bright areas that are out of direct sun and tolerate winter temperatures to 38 degrees Fahrenheit. Fertilize lightly with a balanced solution throughout the active growing cycle, generally spring through fall. For more flowers and fruits, use a fertilizer with no or low nitrogen.

Aphids

• Aphids come in a variety of colors, including green, and are a dominant pest of cacti like prickly pear. They are small pests that reproduce quickly, causing damaging infestations. Aphids feed by sucking sap from the prickly pear, which causes the plant to decline in vigor. If the infestation is bad enough, the stems or whole plant shrivel up and die. Additionally, aphids excrete large amounts of honeydew, a sweet, watery substance that not only attracts other pests, but also breeds sooty mold. Remove aphids by hand or use an insecticidal soap made with clean water and a small amount of mild dish soap. Spray the cactus in the evening hours to prevent sunburn and keep the cactus out of sunlight until the soap dries.

Thrips

• Thrips are another cactus pest that range in color, some adults being greenish-yellow and nymphs a pale green. They are small, slender, fast-moving insects that leap or fly away when disturbed. Thrips suck the juice from prickly pear cacti and leave the stems with a silvery, mottled appearance. Severe infestations stunt growth and damage flowers and developing fruit. Adults overwinter in nearby grass or garden debris, and eggs hatch inside plant tissue and rest in the soil until they molt into adults. A mild solution of neem or horticultural oil controls thrip infestations. Blue or yellow sticky traps hung near the prickly pear cactus catches adult thrips.

Mealybugs

• Some species of mealybugs can appear a yellowish-green underneath the wooly, white film that covers their bodies. The nymphs especially can appear green. Mealybugs cause damage similar to aphids by sucking the plant sap from the cactus and stunting plant growth, which can result in stem or whole plant dieback. Mealybugs also excrete honeydew, which attracts other pests that feed on honeydew, such as ants, and breeds sooty mold. Remove mealybugs by wiping the prickly pear's stems down with rubbing alcohol or using insecticidal soap.