Bonnie Nowicki
In this article, I am addressing a few insects and diseases that interact with plants frequently but rarely cause severe damage. Pests will thrive in an environment where they can get the most food with the least amount of effort. Pests usually choose weak and stressed plants, but healthy plants can also be attacked. They just react quickly by sending out chemicals to stop the attack.
Tiny mites are active now through the fall and enjoy munching on aloes, yuccas, and pyracantha. They pierce and suck juice from plant foliage. One of my 5-foot, mature Spanish daggers (yucca gloriosa) was attacked this year with lots of fine mite webbing. Since I didn’t catch it early with a soapy water spray, I resorted to using a chemical spray. Spittle bugs are also active now through September. White frothy globs appear on rosemary plants and mesquite, ironwood, and palo verde trees. Damage is minimal—just hose off with water.
After heavy rain days, the prickly pear cactus may show signs of Phyllosticta rot. It spreads on the pads in a circular pattern. While the affected pads will always show damage, new pads are healthy. The parasite mistletoe is active year-round on any desert tree. Its bundled mass of small twigs is visually unappealing and is not the same mistletoe used during the holidays. It rarely moves from tree to tree, and the birds feed on the sticky seeds.
Aphids are active through the fall and prefer milkweed, oleander, and roses. These soft-bodied insects suck the juice from tender foliage and leave a sticky residue underneath. Aphids are food for beneficial insects like lacewings. If you don’t want the aphids around, hose them off with water.
There will always be pests in our landscapes. Stay vigilant in all seasons. The most effective way to reduce the impact of pests is to maintain healthy plants. Happy gardening!