Agave plants are popular in many landscapes due to their striking forms and resilience. Though known for thriving in harsh conditions, they are susceptible to pests and animals that can cause significant damage. Understanding these threats is important for maintaining plant health and appearance, ensuring they remain a beautiful part of your garden.
Key Insect Pests of Agave
The agave snout weevil (_Scyphophorus acupunctatus_) is a destructive insect pest targeting agave plants. This brownish-black beetle, about a half-inch long, has an elongated snout. Adult female weevils lay eggs at the agave’s base, typically in spring and early summer. Their bite introduces bacteria into the plant’s core, causing tissue to soften and rot.
Once hatched, larvae (grubs) burrow into the plant’s rotting heart, feeding on decaying tissue. This internal damage leads to the agave’s sudden collapse. While larger species like Agave americana are more susceptible, the weevil can infest various agave types. The bacterial infection, not just larval feeding, is a primary cause of the plant’s demise.
Other insect pests also affect agave, though less severely than the snout weevil. Agave mites (_Oziella_ species), also known as “grease mites,” are microscopic. Their feeding causes cosmetic damage, appearing as greasy streaks or smudges on leaves, which can develop into lesions and discoloration. Severe infestations can stunt growth and lead to plant decline or death.
Mealybugs are common pests, identifiable by white, cottony masses on the plant, particularly at leaf bases and undersides. These sap-sucking insects feed on plant juices, causing stunted growth, yellowing, and deformed leaves. They excrete honeydew, a sticky substance that can lead to sooty mold. Scale insects, similar to mealybugs, attach to agave leaves and stems, sucking plant fluids and weakening the plant. Stressed plants are more vulnerable to scale infestations.
Common Animal Eaters of Agave
Larger animals also pose a threat to agave plants. Deer, generally preferring other food sources due to agave’s tough, spiny leaves and potent sap, may browse on agave during food scarcity or high populations. They eat tender leaves and flowering stalks, and male deer can damage plants by rubbing their antlers.
Rabbits nibble on agave leaves and roots, especially young plants; their damage appears as chewed leaf edges. Javelina, or collared peccaries, are omnivorous and destructive. They dig up plants to eat roots, bulbs, and other parts, including cacti, causing significant landscape disturbance.
Gophers are subterranean rodents that feed on plant roots, causing entire agave plants to collapse. They tunnel underground, eating the soft core and roots, often leaving a concave depression where the plant stood. Rodents like ground squirrels and pack rats also severely damage agaves by eating roots and foliage, particularly during droughts.
Identifying Agave Damage and the Culprit
Recognizing specific signs of damage helps identify the culprit affecting your agave. If an agave wilts, droops, or suddenly collapses with a soft, mushy base and foul odor, the agave snout weevil is a likely cause. A small hole near a leaf’s base may also indicate where the adult weevil burrowed to lay eggs.
Chewed leaf edges, particularly on younger leaves, point to deer or rabbit activity. Deer rubs on larger plants also indicate deer involvement. If entire plants are missing or pulled from the ground with significant root damage, gophers or javelina are strong suspects. Gophers leave characteristic mounds of soil from tunneling.
For insect pests, visual cues are distinct. White, cottony masses in crevices or on leaf undersides signal mealybug infestation, often with yellowing or stunted growth. Scale insects appear as small, flattened, brown or grayish bumps attached to leaves, also leading to stunted growth. Agave mites cause greasy streaks or smudges on leaves, progressing to browning, discoloration, or scar-like lesions. These symptoms appear on the concave side of leaves, facing the core.
Protecting Your Agave from Pests
Protecting agave plants involves cultural practices and targeted interventions. Proper drainage is important, as agave plants prefer drier conditions; excess moisture makes them susceptible to pests like mealybugs and weevils. Avoiding over-fertilization maintains plant health and resilience. Regular inspection for early signs of stress or pest activity allows timely action.
Physical barriers deter larger animals. Fencing at least 4 feet high, with the bottom 4-6 inches buried, prevents deer, rabbits, and javelina from accessing plants. For gophers, lining planting holes with chicken wire or using gopher baskets around the root ball provides protection. Prompt removal and destruction of severely weevil-infested agave prevents spread to neighboring plants.
For insect pests, organic control methods are effective. Horticultural neem oil or insecticidal soaps can be sprayed directly onto mealybugs and scale insects, often requiring multiple applications. For agave mites, which are more challenging, miticides or removing infected plants are options. Introducing natural predators like lacewings or ladybugs helps control mealybug populations. Chemical treatments, such as systemic insecticides containing imidacloprid, can be a last resort for weevils, applied in early spring and late summer, requiring careful adherence to guidelines.