Aphids & Spider Mites on Desert Roses

Spider Mites

• Spider mites are tiny arachnids hard to see with the naked eye. They often produce webbing as protection against enemies and climate changes. According to the University of Florida IFAS Extension, these pests typically feed on desert roses during the warm spring months. Spider mites suck the sap from the leaves, leaving little light flecks on the foliage. Other signs of spider mites include leaf scorch and leaf discoloration. If spider mites are left untreated, these injuries can cause your desert rose to lose its leaves and eventually die.

Aphids

• Aphids are small insects with soft, pear-shaped bodies, long antenna and long legs. These insects pierce plant tissue and suck out the fluids. Aphids often feed in large groups and like to congregate on stems and leaves. Large groups of aphids can cause the leaves of your desert rose shrub to become distorted, yellowed or curled. Aphids also secrete a sticky substance called honeydew. This substance promotes the growth of sooty mold fungus, which can cause your desert rose to turn black.

Monitor

• The best way to control a spider mite or aphid infestation is to catch any potential pest problems early. The University of California suggests checking your desert rose plants at least twice a week during times of rapid plant growth. Inspect the undersides of leaves because aphids often prefer to feed there. In addition, ants like to feed on the honeydew secreted by aphids, so inspect your desert roses when you see a large number of ants crawling on the plants.

Biological Controls

• The Colorado State University Extension reports that the natural enemies of spider mites include predatory mites, predatory thrips, minute pirate bugs and small lady beetles called spider mite destroyers. The University of California notes that lady beetles also prey on aphids, as do lacewings, syrphid fly larvae and parasitic wasps. You can purchase these biological controls from commercial insectaries and online vendors, but biological controls typically work best in small yards.

Chemical Controls

• The University of Florida suggests using a soap-based insecticide to treat spider mite infestations. Insecticides that contain chemicals might damage your desert rose plants. Only use chemical controls as a last resort since pesticides also destroy the natural predators of spider mites and aphids. Follow the directions on the product label, and apply the soap-based insecticide all over the infested foliage, including the undersides of leaves.

Prevention

• Keep your desert roses healthy to help prevent insect infestations. This plant prefers fully sunny locations and warm temperatures up to 90 degrees Fahrenheit. Colorado State University reports that drought-stressed desert rose shrubs that have a change in chemistry appeal to spider mites. Check that you water desert roses regularly during periods of growth, but allow the soil to dry out in between waterings.