NOOOOOOO – agave snout weevil sighting in my garden

In August, I blogged about an agave snout weevil infestation in a friend’s house a couple of blocks away. I was definitely concerned about the agaves in my garden, but I didn’t notice any suspicious signs at the time. Maybe I didn’t take it seriously enough, didn’t look carefully. If I was too complacent, I no longer am now. The day of reckoning has come, because the agave snout weevil is officially here.

Agave shawii × potatorum, a beautiful hybrid by Jeremy Spath

I began with me noticing that the Agave shawii × potatorum in the front yard looked a bit lopsided. Granted, Agave shawii and hybrids involving Agave shawii often have a bit of a lean to them, as if they’re reaching for the sun. But the angle on this particular plant was more pronounced than you would expect. Sure enough, when I nudged it, it wiggled every which way – an agave firmly rooted into the ground wouldn’t do that. It took very little effort to lift the entire plant straight up.

This is what I found on the underside:

If you read my post about my friend’s Agave americana ‘Mediopicta Alba’, you’ll recognize the culprits:

In mid-summer, when we discovered the infestation on my friend’s agave, the snout weevils were very active, immediately scurrying out of sight to hide from the light. Not so now in early December: The weevils in the photos above were barely moving.

After an expletive-laden outburst of frustration and disgust, I quickly snapped the photos above and then tossed the infested agave in the garbage. In hindsight, it’s possible I could have saved the plant by cutting off the rotten tissue at the bottom, but I was too eager to get it out of my sight.

Next, I dug up what was left in the ground (mostly roots) and thoroughly drenched the area with imidacloprid solution (12 ml of 21.4% imidacloprid to 5 gallons of water). Imidacloprid kills snout weevils on contact. Be very careful when using it around flowering plants; it’s absorbed by the plant through its roots and then translocated throughout the plant tissue all the way into the flowers. As a neonicotinoid insecticide, it represent a risk to wild bees and honeybees. It’s less of a concern in non-flowering plants because bees don’t suck the plant juices like many pests do.

Out of an abundance of caution, I proceeded to drench the root zone of all agaves nearby with imidacloprid. I will repeat this step in a week, just to be on the safe side, and then again in the spring. That’s about all I can do, other than cursing some more and keeping my fingers crossed.

For more information on agave snout weevils, refer to my post from August as well as these resources:

• Agave Snout Weevil, Coming to a Garden Near You (Debra Lee Baldwin, Gardening Gone Wild)
• Agave Snout Weevil Prevention and Treatment (Debra Lee Baldwin)
• Agave and yucca weevils—Scyphophorus species (University of California Statewide Integrated Pest Management Program)
• Agave Snout Weevil—Desert Gardening Guide (Desert Botanical Garden, Phoenix)
• Agave Weevils: a Water-wise Gardener’s Nightmare (SF Bay Gardening; info of particular interest to Northern California gardeners)

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