Agave Snout Weevil

Agaves and yuccas are beautiful ornamental plants that are often used to accent xeriscape gardens. For the most part, they do not have serious pest problems. However, there are a few exceptions and learning to recognize their presence is important to maintaining these plants’ health.

Snout weevils are probably the most damaging pests to agaves and yuccas. The agave snout weevil (Scyphophorus acupunctatus), also known as the sisal weevil, feeds on many species of agave and can be especially damaging to the larger species such as century plant (Agave americana) and blue agave (Agave tequilana). It will also feed on other agave species. The agave snout weevil is also a serious pest where blue agave is grown commercially for tequila and in foreign countries where agaves have been introduced as landscape plants. A similar species also colonizes yuccas.

Snout weevils are beetles about 1⁄2 inch (12 mm) in length, brownish-black and have a dull body. Being a weevil, it has a protruding snout and chewing mouthparts. The adult female enters the base of the plant to lay eggs in the spring. These eggs hatch into larvae (grubs) that feed on the succulent core of the plant. Decay microbes also enter through this injury rotting plant tissue causing the plant to collapse. Infested plants soon collapse and die. The larvae have chewing mouthparts and develop in the dying plant and infect other hosts nearby.

Control of the agave snout weevil is difficult. Selecting species that are less susceptible and typically smaller than the century plant is helpful, especially in areas where the problem has occurred previously. Minor infestations can be controlled by removing and discarding the affected plants. With rare or special specimens, chemical prevention using a broad-spectrum insecticide applied in spring is often effective in reducing damage. Diazinon granules were once used to control agave snout weevils, but diazinon is no longer available. Imidacloprid granules (Merit) applied in the early spring are a suitable replacement when pesticides are deemed necessary. But why use a chemical pesticide when an organic alternative is available that will not harm the environment and does not affect the food chain?

Weevil Wipeout has proven 95% effective in clinical trials against Scyphophorus acupunctatus.