The yucca plant is a member of the Agavaceae family and is a flowering plant found in many yards and home gardens. While this plant is generally healthy, it is susceptible to infestations of a red, yellow, and black insect known as the yucca plant bug, which damages yucca plants by feeding on foliage Identification The yucca plant bug is also known by its scientific name of Halticotoma valida. The insect is red, yellow, and black in color and causes damage to yucca by feeding on its leaves. Both adult yucca plant bugs and nymphs cause damage to yucca by sucking plant sap from the leaves with piercing mouth parts. Effects Yucca plants infested with the yucca plant bug develop feeding injuries from the insect's sharp mouth parts. Adults and nymphs feed on foliage of the yucca plant, causing leaves to turn yellow. New foliage often becomes stippled or speckled from yucca plant bug feeding and is more susceptible to the effects of this pest than older plant leaves. Soaps and Oils Insecticidal soaps are often effective in controlling the yucca plant bug on infested plants. Spraying your plant with insecticidal soaps and washing the soap from the plant is one way to eliminate this pest. Horticultural oils work by covering up the air holes of the yucca plant bug, causing it to suffocate. Both of these control methods rely on contact with the insect to kill it, making it necessary to completely cover the plant when applying them. Concentrate on the undersides of plant leaves when applying soaps or oils, as this is where many insects congregate to feed. Chemical Control There are several types of chemical control methods recommended for yucca plant bug control. Malathion is one chemical that is available at your local garden center and can eliminate the yucca plant bug. Other products such as foliar sprays work on contact with the bug. Cover the entire plant thoroughly for best results. Repeat application of chemical control products periodically to prevent re-infestation. -Birdy