Weevil evidence?

[Hillrg]

I’ve attached some photos of apparent punctures on the center leaves of a couple of my agave. It looks like the sap has oozed out and hardened as an attempt to heal, but I’m wondering if these are marks from weevils laying eggs. One of them is still looking very healthy, but the other is leaning and lower leaves are not doing well.

Any recommendations on how to proceed would be appreciated, thanks.

[mcvansoest]

Definitely very concerning and about the right size for Weevil holes. The one that has floppy out leaves and a leaning core - see if the core is still attached usually by the time the outer leaves go floppy/flat to the ground the core tends to be mush and easily removable - hence the lean. Weird time of year unless they are exit holes. Anyway on that bad plant if there are weevils you would probably see clear evidence if the core comes out easily.

[Hillrg]

Core seems to be very much intact still. Do you mean that hatched weevil larva could be exiting around this time of year? Should I dig it up and look for evidence of pests? Planted these a little over a year ago, so they’re not super established yet.

[mcvansoest]

Yup, usually the infestation with weevils happens in the late winter - spring and you start seeing the evidence in summer - early Fall. Now that that is not to say a fresh infestation right now is impossible, but usually the floppy leaves come later in the cycle.

Looking at the holes again they are a little high up on the core for where I would normally expect weevils to enter the plant, but that does not necessarily mean anything. I'd definitely consider treating the plants with a systemic with imidacloprid. Not sure what digging up the plants would get you - except to stress out a stressed plant even more. When did you water them last?

[Hillrg]

Got it, my main concern is keeping any pests from spreading to our other agave, so I wasn’t sure if removing the affected ones was an important preventative step - I’m definitely a novice with this though. I watered them 3 or 4 days ago, for the first time in a month. Temps have been in the high 80s the past few weeks here in the Phoenix area.

[mcvansoest]

I'd go for the systemic, just water all your Agaves with it just in case there is weevil activity. Keep an eye on those plants with the boreholes...

Weevils are weird in how they target their victims, they may just go for one specific Agave or one specific Agave species - for example at my old place where I grew at least 25 different agave species in the ground they only ever went for Agave weberi even though I had plenty of other large-ish agaves growing leaving everything else alone. That is not to say they could not go for other Agaves in your yard, but just that they generally are not a infest everything there is kind of bug at least in my experience.

While it has been cooler, it has been super dry, so some of the droopy leaves could just be thirstiness.

[Hillrg]

Have treated all with Imidacloprid, will hope for the best! I’ll treat again in the spring, unless you recommend a different schedule?

And I have 6 agave weberi, so my backyard may be a weevil heaven unfortunately…