Landscape designers are experts at studying a neighborhood to see what plants grow well in the immediate microclimate. If there aren’t any older specimens of a certain plant, chances are it’s been wiped out at some point by a freeze, drought, disease or pest infestation. I should have known when I found just one well-established agave around here in Palm Springs. All the other agaves were still young – in plantings less than 5 years old.

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The female snout nose weevil punctures holes in agaves to create a place for its eggs, which develop into hungry grubs that devastate the plants.

Photo Credit: Maureen Gilmer

Snout Weevil grub in plant

This upside-down agave reveals the mealy tissue and the guilty grub that severed every root from this afflicted plant.

Photo Credit: Maureen Gilmer

Agave close up

Soft, thick-leaved agave species tend to be the most attractive to snout nose weevils.

Photo Credit: Maureen Gilmer

Agave angustifolia

Thin-leaved, fibrous Agave angustifolia appears to be the most resistant species, thriving where all others are devastated by snout nose weevil infestations.

Photo Credit: Maureen Gilmer

Now, agave is about as tough a plant as you’ll find, and it takes a lot of abuse to cause it to wilt. In fact, nothing kills it. At least that’s what I thought – until my biggest specimen, an Agave americana ‘Mediopicta Alba’, suddenly melted down overnight, leaving just the central cone of tightly packed leaves upright. The whole thing just flopped over at my touch to reveal a shocking lack of roots! The insides had become a brown mealy mess completely riddled with fat, white grubs that had obviously done the damage.

My desert plant guru, Clark Moorten, smiled when I showed him the tragic remnant.

“That’s the worm in the bottom of the tequila bottle,” he said. “They’re the grub of the agave snout nose weevil (Scyphophorus acupunctatus). They devastated the blue agave fields in Mexico. We’ve always had them in this area, which is why you won’t see any big Agave americana species in the valley. It’s their favorite meal!”

Since then, I’ve never planted another agave – except in pots where they don’t have any contact with natural soil. (That’s where the weevil pupates from grub to adult.)

The snout weevil is about ½ an inch long and distinguished by its very pointy proboscis. When ready to reproduce, the female beetle finds a nice succulent agave and sticks its long nose deep into the tissues of the fleshy central cone of tightly packed leaves. If you look closely, you can spot the brownish puncture long before the plant shows any other weevil symptoms.

The beetle’s saliva introduces fast-moving microbes to the inner tissues, which spread at an alarming rate. The microbe-infested flesh becomes more edible for the female’s young larvae, speeding up the plant’s demise.

The beetle then lays her eggs in the hole she’s made. Larvae hatch and begin voraciously tunneling through the vital water-transporting tissues at the very center of the plant. They work their way down to the soil, where they sever the plant from its anchorage and water source. When there’s nothing more to eat, the grubs exit into the soil where they pupate – then the whole process starts all over again.

Soils in some gardens can become rich with weevil pupae that will infest any agave planted there. Some aged plants manage to resist the beetles, and we know these individuals are unique due to their very survival. Experts say the genetically identical offsets (not seedlings) from these plants should make resistant breeding stock for afflicted regions, but that’s a long-term solution.

One way gardeners are coping with this evil weevil in the short term is laborious and time-consuming: They dig up the whole area and sift out all the pupae, grubs and beetles they find. Then they remove the soil and replace it with clean, uncontaminated earth. Another option is to use diatomaceous earth around the plant to keep the pests away, but this has to be replaced each time you water or after a rain. Obviously, both solutions are problematic.

As a rule, I restrict the use of pesticides, but I make an exception where the snout nose weevil is concerned. Some success has been had with granular grub killers applied to a large area of soil around the plant. (It’s best applied in March and again in June, when the beetles are most active.) If used according to the manufacturer’s instructions, it can be effective at killing both the soil-borne grubs and preventing hatchlings from feeding on the plant. It may not, however, deter adult beetles from puncturing the stems and introducing the damaging bacteria.

So before you invest in a beautiful agave garden, have a talk with a professional at your local garden center or Cooperative Extension office to see if your neighborhood might be at risk for snout nose weevil. With large-specimen succulents costing hundreds of dollars each, you may decide to follow my lead and plant aloes instead.