Agave Americana's after being infested with what I am sure is the agave snout weevil. I have read about this scourge of low desert gardens before and felt lucky that my agave's until this point had not been affected. Now I am unable to say that.
I noticed on Friday that on of the agaves was looking rather flat and assumed that Tex had trampled it in his constant quest to catch a lizard. However on closer examination I saw that the entire plant had collapsed and I was able to pull out all the leaves leaving only the heart which fell over soon after. As I cleared it all away there was a foul smell which I now know is a classic sign of this pest.
The female weevils chew their way into the heart of the agaves in the spring leaving bacteria as they go. They then lay their eggs which hatch out to produce the next generation of adults. Signs often appear in the infested agave in the summer after the life cycle has been completed and it is actually the bacterial infection that kills the plant which is why the smell is so bad. At this point it is too late to save the plant. The only treatment appears to be application of a strong pesticide in the spring to prevent infestation. There is more great information here about this pest here from the wonderful Desert Botanical Garden.
Although I am really sad to lose such a lovely specimen I absolutely don't want to use any toxic chemicals in my yard and so I will just have to let nature take its course, and be prepared for what may follow. Agave Americana is a particular favorite of mine with it's huge sculptured look but if they are all affected by this I am prepared to avoid planting them in the future. This is the way of gardening sometimes hard though it may be. I am just glad I haven't lost a tree, that would be far worse.
Here are the agave's that are left standing right next to the affected ones.
Even gardening can be sad sometimes.
A Tucson Spring
7 hours ago