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Saturday, October 14, 2017

Got agave problems? It may be this common pest.



The agave is one of my favorite plants. Nothing quite compares to its dramatic form, making it a great choice to add interest in desert landscaping. While both low water use and normally maintenance-free, the agave does succumb to an annoying insect that decimates the entire plant with little notice that there is a problem until it is too late.

The symptom of snout-nosed agave weevil damage almost looks like the plant is wilted from lack of water.


However, this is not the case. What has happened is that the weevil has chewed a hole into the center bud of the plant. While doing so, they excrete an enzyme that softens plant tissue, allowing bacteria, fungi and diseases to take hold. When the female lays her eggs, the white grubs that hatch eat the plant from the inside out. This process takes 2 to 3 months. Once you see the damage, the plant is dead and there is nothing you can do to save it. I’m not a proponent of systemic insecticides, which you may read is an option. I prefer to recommend you avoid the species of agave that is the most susceptible to snout-nose agave weevil attacks: the Century Plant. (Agave Americana, photo)

Proper plant care also reduces susceptibility to insects and diseases. With agaves, less water is more. Over-watering these plants, if it doesn’t cause roots to rot, speeds up their growth, shortening their lives. When an agave reaches maturity, it will flower and die. And despite what you may have heard, cutting off the flower stalk will not make it live longer.

If you want your plant to live a nice, long life, anywhere from 5 to 25 years (depending on the variety), monitor the water schedule carefully. For plants in the ground, water once a week in the summer, and once a month or so in the winter, depending on winter rains. Container plants in full sun will need twice that, usually twice a week in the summer and twice a month in the winter.

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