Agave Mite

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Gee.S
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Agave Mite

#1

Post by Gee.S »

I thought it best to begin with pics that depict eriophyid mite infestation, since identification can be a tricky business. Some are garden plants, others are in habitat.

Note lesions and accompanying grease stains. If you see an Agave with lesions, but no grease stains, it is probably not eriophyid mite damage. Also note that lesions always occur on the core, posterior leaf surfaces, and leaf edges. If lesions are restricted to anterior leaf surfaces, it is not eriophyid mite damage.

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Agave
"American aloe plant," 1797, from Greek Agaue, proper name in mythology (mother of Pentheus), from agauos "noble," perhaps from agasthai "wonder at".

"Some talk the talk, others walk the walk, but I stalk the stalk"
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Re: Agave Mite

#2

Post by Gee.S »

Many of us have successfully knocked down mite infestations. I don't doubt that some Agaves are more prone to infestation than others, and there may be more than one reason. Some species may be more resistant than others due to chemical makeup (sapogen content, for example), and some individual plants may be more resistant to infestation than others, by virtue of general health/condition. And it is not unlikely that multiple Agave mite species are in play. We have found Agave mite in nurseries and in situ across Arizona, as well as habitat examples of apparent recovery from mite infestation, so Agaves do not appear entirely defenseless. Happy, healthy Agaves might manage to put up a better fight than those less suited to our garden environments.

Note lesions and accompanying grease stains. If you see an Agave with lesions, but no grease stains, it is probably not eriophyid mite damage. Also note that lesions always occur on the core, posterior leaf surfaces, and leaf edges. If lesions are restricted to anterior leaf surfaces, it is not eriophyid mite damage. It is important to understand that the type of damage/evidence shown in the prior post may take months to develop, and you cannot take a measured approach when treating. If you limit treatment to those plants with obvious mite-sign, you'll just play whack-a-mole until the end of time. Assume that any and all Agaves in the vicinity of an obviously mite-infested plant are themselves, infested, whether or not they are symptomatic. Best to abandon any and all thought of a measured response, you'll need to hit 'em hard, and keep hitting 'em hard.

If Agave mite has entered your collection, and evidence of contamination is found on more than one plant, rotate at least two translaminar miticides (three is preferable), spraying your entire collection top to bottom (but mostly the top) at 4-week intervals, deferring to miticide instructions. You can skip spraying in winter months so long as low temperatures dip below freezing on occasion, as mites recede deep into the core out of reach at this time. Here in sunny AZ, that is usually mid-December through mid-February. Resume spraying late winter/early spring, paying close attention to the condition of all your plants. Mite-infested Agaves not only carry grease-stained lesions on and about the core, they also fall into a general malaise, which basically presents as dormancy. These plants do not offset, and grow very slowly, if at all.

Continue to spray all of your Agaves until all of your Agaves are growing and/or offsetting and have three new clean (lesion-free) leaves. This may take a year or more. Minor infestations that don't move beyond 2-3 plants in close proximity may be easier to contain and address. Just stay vigilant and pay very close attention to the condition of all your Agaves. If you know mites are about, suspect infestation of slow-growing plants even if no lesions are present.
Agave
"American aloe plant," 1797, from Greek Agaue, proper name in mythology (mother of Pentheus), from agauos "noble," perhaps from agasthai "wonder at".

"Some talk the talk, others walk the walk, but I stalk the stalk"
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Re: Agave Mite

#3

Post by Gee.S »

Here are links to a few threads that feature more detailed exchanges regarding mites and treatment.

Habitat Agave Mite
First the hog snout damage, now the snout weevil?
My African Adventures
Matt Maggio's Mite Management Method Works
Agave
"American aloe plant," 1797, from Greek Agaue, proper name in mythology (mother of Pentheus), from agauos "noble," perhaps from agasthai "wonder at".

"Some talk the talk, others walk the walk, but I stalk the stalk"
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Re: Agave Mite

#4

Post by Gee.S »

Reference was made above to "evidence of contamination is found on more than one plant". If evidence is found on but a single plant, and that plant is either a new addition or at least somewhat isolated, or better yet, quarantined, it may be preferable to destroy that plant and keep your fingers crossed that contamination has not spread to the rest of your collection. It's a gamble, but may be a good one, dependent upon specifics, in hopes of avoiding a protracted and expensive battle.
Agave
"American aloe plant," 1797, from Greek Agaue, proper name in mythology (mother of Pentheus), from agauos "noble," perhaps from agasthai "wonder at".

"Some talk the talk, others walk the walk, but I stalk the stalk"
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Re: Agave Mite

#5

Post by Viegener »

These are the most useful pics of mite infestation I've seen. I never quite understood the "grease stain" until now.
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Operation Agave Might

#6

Post by Gee.S »

This download provides a more thorough consideration of the issue. The article is extremely informative, but five years old, when folks were really just starting to sort the mite issue out.
Operation_Mite.pdf
Operation Agave Might
(1.64 MiB) Downloaded 1130 times
Agave
"American aloe plant," 1797, from Greek Agaue, proper name in mythology (mother of Pentheus), from agauos "noble," perhaps from agasthai "wonder at".

"Some talk the talk, others walk the walk, but I stalk the stalk"
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Gee.S
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Re: Agave Mite

#7

Post by Gee.S »

Viegener wrote:These are the most useful pics of mite infestation I've seen. I never quite understood the "grease stain" until now.
Once you've seen it up close and personal a few times, the look is unmistakable. You'll notice one photo features grease stains with no lesions. That is early stage mite infestation. And all photos feature some level of discoloration. No stains, no mites.

BTW, Amazon has a couple inexpensive offerings for Agave mite treatment. These include Pylon Miticide and Forbid 4F.
Agave
"American aloe plant," 1797, from Greek Agaue, proper name in mythology (mother of Pentheus), from agauos "noble," perhaps from agasthai "wonder at".

"Some talk the talk, others walk the walk, but I stalk the stalk"
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Re: Agave Mite

#8

Post by Spination »

Agave potatorum Verschaffeltii Ikiri Raijin Nishiki. Apparently an unusual example of mite infestation damage on leaves, rather than usually limited to the base of leaves from the core...
2017 12 13 A potatorum Verschaffeltii Ikiri Raijin Nishiki b.jpg
2017 12 13 A potatorum Verschaffeltii Ikiri Raijin Nishiki b.jpg (87.17 KiB) Viewed 15375 times
bigdaddyscondition
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Re: Agave Mite

#9

Post by bigdaddyscondition »

My experience so far confirms everything Gee discusses above in his exposition of the mite problem. It's very helpful that you included Matt Maggio's excellent and comprehensive article from the Cactus and Succulent Journal. I ordered my own copy of that issue, which was mailed to me from the next town over, Claremont, CA, the HQ of the CSSA.

One caveat about Forbid 4F, mentioned by Maggio in his article: it can cause deformation of developing leaves. The plant will recover, but in the meantime you'll have a distorted clump of misshapen, stunted leaves in the center of your agave. Of the 30-odd species in my yard, only my Agave impressa has suffered this phytotoxic effect. When it's time for a Forbid 4F application, I drench the impressa with Sevin instead.
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Re: Agave Mite

#10

Post by DesertDweller »

bigdaddyscondition wrote:My experience so far confirms everything Gee discusses above in his exposition of the mite problem. It's very helpful that you included Matt Maggio's excellent and comprehensive article from the Cactus and Succulent Journal. I ordered my own copy of that issue, which was mailed to me from the next town over, Claremont, CA, the HQ of the CSSA.

One caveat about Forbid 4F, mentioned by Maggio in his article: it can cause deformation of developing leaves. The plant will recover, but in the meantime you'll have a distorted clump of misshapen, stunted leaves in the center of your agave. Of the 30-odd species in my yard, only my Agave impressa has suffered this phytotoxic effect. When it's time for a Forbid 4F application, I drench the impressa with Sevin instead.
Just an FYI, as I posted separately here, but Sevin is no longer rated for mites.
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Re: Agave Mite

#11

Post by bigdaddyscondition »

Oh, swell! Thanks for that very valuable information, DesertDweller. I am compulsive about checking labels, but I could have missed that if I were in a hurry down at Home Depot. Good thing I'm stocked up on the real thing, with carbaryl.

(duplicate post, also posted on your linked thread)
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Re: Agave Mite

#12

Post by DesertDweller »

Gee.S wrote:Prolonged treatment for mites invariably leads to fused and/or deformed leaves in my experience. And yes, Forbid 4F is one of my miticide trifecta. I had always assumed the issue stemmed from prolonged translaminar use (of any kind), possibly exacerbated by my use of adjuvants, per miticide label recommendation. In fact, I feel quite certain that the fusing is from just that, but perhaps other deformities are caused by Forbid. Either way, fused leaves within the core are a far more serious problem, as the deformities are minor and cause no lasting issues.
For whatever it is worth, I have started to heavily soak new acquisitions in Forbid 4F, sans adjuvant, and as yet had no issues with fusing or deformity of any kind, so I think you may be on to something there. In fact, the reason I hesitated to use adjuvant was exactly this issue.
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Re: Agave Mite

#13

Post by bigdaddyscondition »

But then is the miticide penetrating into the little crevices and nooks and crannies of the treated plant as well as it would with the surfactant? Yes, Forbid 4F is translaminar and so theoretically should penetrate the interior anyway, but it seems intuitive that your chances of systemic absorption by the plant are better if you maximize the surface wetted.
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Re: Agave Mite

#14

Post by DesertDweller »

bigdaddyscondition wrote:But then is the miticide penetrating into the little crevices and nooks and crannies of the treated plant as well as it would with the surfactant? Yes, Forbid 4F is translaminar and so theoretically should penetrate the interior anyway, but it seems intuitive that your chances of systemic absorption by the plant are better if you maximize the surface wetted.
I tried to balance the lack of surfactant with heavy soaking, multiple times to runoff, during application. These were pretty small plants, I should add, so another reason I didn't want to take chances with surfactant.
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Re: Agave Mite

#15

Post by mcvansoest »

I am pretty sure it is the surfactant. I have not splurged for Forbid yet, but I have Avid and unless that is the culprit, I unfortunately have a couple of Agaves with some interesting deformities from the spreader sticker. One is going to be just fine as it is just some conjoined leaves, but the other an Agave potatorum has pretty badly inter grown leaves in the core. I think they may come apart, but it is not quite clear yet...
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Re: Agave Mite

#16

Post by Gee.S »

Everything is a non-issue if you've never had it happen. I've had it happen several times, because I have actually had mite issues here. Once because I was purposely bringing mite-infested Agaves home, but the other time was accidental. Sometimes you can pull fused leaves apart, but the only remedy a couple times was to cut fused leaves apart with a knife. At one time Arid Lands had hundreds, perhaps thousands of young plants with the issue. Their issue was caused by massive overspraying of plants with translaminars, and was not resolved until I told them the cause.
Agave
"American aloe plant," 1797, from Greek Agaue, proper name in mythology (mother of Pentheus), from agauos "noble," perhaps from agasthai "wonder at".

"Some talk the talk, others walk the walk, but I stalk the stalk"
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Re: Agave Mite

#17

Post by Melt in the Sun »

I'll throw in my anecdotal experience as well - I have never had issues resulting from my own spraying. I use forbid and spreader-sticker.
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Re: Agave Mite

#18

Post by Gee.S »

90-2 Parker.pdf
Agave Mite: A Quick and Dirty Primer
(2.74 MiB) Downloaded 1840 times
Agave
"American aloe plant," 1797, from Greek Agaue, proper name in mythology (mother of Pentheus), from agauos "noble," perhaps from agasthai "wonder at".

"Some talk the talk, others walk the walk, but I stalk the stalk"
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Re: Agave Mite

#19

Post by bigdaddyscondition »

Thanks for this review, Gee. The photos very clearly show the pathognomonic signs of mite infestation.
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Re: Agave Mite

#20

Post by jthiel23 »

Regarding the fused leaves. I think this is happening to a few of my agaves. What can I do? Do I just have to let them grow out of it?
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Re: Agave Mite

#21

Post by Gee.S »

Pull 'em loose when you're able. If it's really bad, you may need to cut them free with an exacto knife. And be careful not to overspray.
Agave
"American aloe plant," 1797, from Greek Agaue, proper name in mythology (mother of Pentheus), from agauos "noble," perhaps from agasthai "wonder at".

"Some talk the talk, others walk the walk, but I stalk the stalk"
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Copied from another thread....

#22

Post by Gee.S »

I've been thinking about 'fused leaf syndrome', and believe it entirely possible that spraying translaminar miticides too thoroughly can not only harm our plants, but actually impair their ability to resolve the mite issue. I have seen a LOT of mite damage out in habitat, and regularly come across agaves that have cleansed themselves of mite infestations. I have also noticed that mites have been spreading like wildfire in AZ over the past few years.

So first, why have mites been spreading so rapidly out in the wilds? I suspect prolonged drought conditions, which weaken agaves and make them more susceptible to infestation from any number of pathogens, including mites.

And second, how do they recover? I don't know, there are myriad possibilities, but I suspect a few good douses of rain on plants that haven't been too severely weakened, improves their defensive abilities, and may contribute to their recovery.

If we accept these premises, then it may actually be possible for our garden plants to recover without chemical intervention, if we can get them happy and healthy enough. Of course, that will never happen across entire collections, but it would be interesting to experiment on quarantined individuals. In any case, the point I am leading to is that a chemical treatment so severe that it starts fusing leaves within the core, must place an inordinate strain on the plant, and severely hamper its ability to recover. A further point is to assess the reason(s) garden plants contract mites in the first place, and consider improving living conditions via hydration, more comfortable sun exposure, and perhaps even soil amendment as part of a treatment program.
Agave
"American aloe plant," 1797, from Greek Agaue, proper name in mythology (mother of Pentheus), from agauos "noble," perhaps from agasthai "wonder at".

"Some talk the talk, others walk the walk, but I stalk the stalk"
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Re: Agave Mite

#23

Post by bigdaddyscondition »

Food for thought, gee, thanks. I tend to spoil my agaves, providing amended soil with organic matter in the Inland Empire's sandy soil, broken down from erosion of the San Gabriel Mountains. I fertilize them usually once a year in early spring. And I have learned pretty much when they need some extra water in our dry summers, including the differing water needs of the various species. I have been lucky to avoid a lot of mite misery in my garden collection. Maybe it's a result of the coddling I give them, as you speculate.
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Re: Agave Mite

#24

Post by Gee.S »

Perhaps so, but you know, most all gardeners try plants that are marginal for their areas, myself included, and such agaves may remain stressed at times despite our best efforts.
Agave
"American aloe plant," 1797, from Greek Agaue, proper name in mythology (mother of Pentheus), from agauos "noble," perhaps from agasthai "wonder at".

"Some talk the talk, others walk the walk, but I stalk the stalk"
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Re: Agave Mite

#25

Post by bigdaddyscondition »

What human can match the wisdom of natural selection?
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