The agave snout weevil [Scyphophorus acupunctatus], also known as the Sisal weevil, is abundant in the southwestern United States and also throughout Mexico.
They feast on many species of agave plants and other plants in that family.
The adult snout weevil is a large black beetle with a long and pointy snout.
These beetles are especially damaging to large agave species, such as the century plant. This plant and its cultivars are very popular in landscaping in the southwestern United States and other hot, dry areas.
The beetles are a real threat to the blue agave, which is used to make tequila.
The “worm” often found in the bottom of a tequila bottle is actually an agave weevil larva.
In this article, we describe the snout weevil, its larva, and the damage wrought by both. Read on to learn more.
What Damage Does The Agave Snout Weevil Cause?
Agave weevil beetles wreak havoc with Agave century plants and many native agaves throughout the states.
The snout weevil also causes tremendous damage and financial ruin to growers of blue agave in Mexico.
Adult beetles seek out plants primarily in a weakened state. They especially target recently bloomed agave plants.
These plants Agave americana (aka: Century Plants) bloom once in their lifetime and then go into decline and die.
If the damage caused by the agave beetle was isolated to individual plants, their existence would not be problematic.
Unfortunately, when the agave snout weevil infestation attacks a declining agave plant, the effects of its attack spread to the plant offshoots (pups) and all of the agaves in the immediate vicinity.
How The Agave Snout-Nosed Weevil Works
The agave weevil bites the plant and injects bacteria, which causes the plant tissues to liquefy and soften.
The beetle then lays eggs in the flesh of the plant. When the eggs hatch, they easily feast on the soft, liquefied plant tissues.
The combined attack of the agave weevil larvae and injected bacteria caused the plant to collapse.
Agaves affected by this bacteria fall apart. The center of the plant (from which tequila is made) becomes mushy and takes on a foul odor.
The bacteria spreads to the pups and to neighboring plants causing them to collapse as well.
When the effect of the snout weevil attack progresses this far, there is no point in trying to save the plant. It is dead!
It’s very important to remove every trace of it (and surrounding agave plants) from your garden.
Dispose of the agave plants completely to prevent the spread of the bacteria.
How To Prevent Snout Weevil Infestation
It’s very hard to deal with snout weevil control because:
- They are large (about half an inch long)
- Have hard shells
- The snout weevil “hides” very effectively within the agave plant leaves
Even so, use the least toxic agave snout weevil treatment, repellent, and insecticide available such as:
… as a precaution, before the beetles appear could be helpful.
Plant Agave Cultivars Unattractive To Snout Weevils
Another way to prevent or control agave weevil attacks is to plant agaves that weevils find “not attractive.”
Horticulturists are working hard to develop specific snout weevil-resistant cultivars.
As a general rule, snout beetles seem less attracted to agaves like the Agave Attenuata species with:
- Flexible, thin leaves
- Very hard to pierce leaves
- Tough leaves
- Very slender, dry leaves
Snout Weevil Treament – How Do You Get Rid of Snout Nose Weevils and Their Larvae?
If you see an agave snout weevil, it’s probably too late for precaution.
At this point, use a systemic pesticide such as Triazinon to kill the beetles and the larvae as they feast on your plant.
Even so, saving the plant may not be possible. However, it may be possible to prevent the pests spreading and bacteria.
Systemic pesticides are applied to the soil surrounding affected plants.
When the plant receives water, the chemical is slowly released. The plant roots take up systemic insecticide and spread throughout the plant tissues.
Monthly application is recommended.
You must be careful when using these types of pesticides. They can have unintended effects and may also kill beneficial insects.
Don’t use systemic pesticides on flowering plants because you end up killing pollinators who visit the blossoms.