By Scott Calhoun
The warmer weather of spring brings tender new growth and colorful blooms to our gardens, but it also brings some of our most unwelcome garden guests. Knowing what to watch for will help you catch problems early and mitigate the damage these pests can do.
Aphids show up early and reproduce quickly, laying eggs and giving birth to live young. The easiest way to control aphids is spray them off with water, but insecticidal soap works as well. To control completely you may need several applications.
White, cottony growth, often seen on prickly pear cactus, actually is the protective coat over a tiny, red insect called cochineal scale. Cochineal scale is difficult to control with topical pesticides, but a hard spray of water knocks them right off.
Wide-leaf agaves, such as Agave americana and Agave weberi, are particularly susceptible to agave snout weevil. Watch for leaves that droop, leaving only a wrinkled central meristem. But often, by the time you recognize those rather sudden signs of an infestation, your plant has been irreparably damaged.
Prevention is the best medicine for the snout-nose weevil. Use a systemic insecticide combined with fertilizer for best results. I use a rose fertilizer with a systemic in it.
Caterpillars present a dilemma: Allowing them to chew freely can defoliate your plants, but if you let them stick around you’re likely to have butterflies fluttering about your garden later. Controlling them is easy if you prefer perfect foliage now instead of butterfly visitors later. Physically picking them off is an easy option for small numbers. You can control larger infestations with Bt (Bacillus thuringiensis), a bacterium safe for people.
Javelinas eat just about anything, but they do have their favorites. You may need to protect plants, such as red yucca, with hardware cloth to prevent them from becoming midnight snacks.