Matt Maggio's Mite Management Method Works

[bigdaddyscondition]

It worked for me, anyway. Some of you may remember my travails with agave mite control, related in several posts on another xeric forum a few years back. At that time I consulted Matt Maggio's excellent review article, "Operation Agave Might! Combating Eriophyoid mite of Agave", Cactus and Succulent Journal, vol. 84 no. 6, November-December 2012, pages 283-291.

A young Agave 'Sharkskin Shoes' in my front yard developed mite sign about three years ago, with faint rust-colored streaks on the abaxial surfaces of its newer leaves. Knowing that this species produces offsets, I applied the Maggio Method as described in the article. I transected the apical meristem of the diseased plant, drilled out the core with a one-inch spade drill bit, and assured drainage of rainwater from the drilled-out crown by sawing a channel in it. I completed the process by drenching the cored-out plant in Forbid 4F.

Over the following year or so the still-living remnant of the cored-out parent plant produced six or seven healthy offsets with no mite sign. I harvested and potted these, eventually replacing the cored-out parent plant with one of them (see photo of plant in the ground). I repotted three others in Serralunga pots on my deck (see deck plants photo). So far all plants appear healthy and happy.

[Spination]

I've also been able to rid affected agave (a few years ago now) using Forbid, but without mutilating the plants... The common denominator is the miticide - systemic, translaminar, proven effective.

[bigdaddyscondition]

I've also saved a few with early mite sign by simply spraying either Forbid 4F (spiromesifen) or Avid (abamectin), both good translaminar agents. But I've had failures too. I suspect that host factors play the biggest part in mite susceptibility, with some species simply being more likely to infestation. Maggio's article mentions several species that are more susceptible in a section titled "Favored Hosts." It reflects my experience, since two of the species I've had with infestation (titanota and palmeri) are on his list. I've also had to dispose of a havardiana that was showing mite streaks when I bought it at a well-known Los Angeles area nursery before I knew much about agaves.

In this case I simply wanted to maximize my chances of success in eradicating the mites from this especially handsome plant so I could propagate it.

[KLC]

I've also been able to rid affected agave (a few years ago now) using Forbid, but without mutilating the plants... The common denominator is the miticide - systemic, translaminar, proven effective.

^^^This.

[bigdaddyscondition]

KLC, are you saying the coring method is unnecessary? You've had success just overhead spraying with miticide? Details please.

[Spination]

I'm not going to speak for Keith, but that's my interpretation. Personally, my success with "overhead" spraying was with a rotation of Forbid 4F, followed in a couple of weeks with Avid. My definition of "overhead" might not be the same as what you're imagining. I spray the krap out of the plants. On top of the leaves, under the leaves, until they are sopping soaked with spray. Also, using the recommended range of mixing strength, I don't mess around. I use the strongest recommended mixing rates given on their product sheet (without double checking - I think it was 2 ml per gallon). Finally, when mixing a gallon at a time, I just go over the plants again if there's anything left, until the sprayer is empty. I don't like storing mixed product in anything more than a single 16 oz spray bottle. And, I can assure you, this did work for me, with no more Agave mite damage to be found for the last couple of years following.

As far as what you did, using MM's method, I can see in particular the value of the procedure. It was a combo miticide treatment, and coring operation, in which you achieved 2 goals concurrently. I don't see any problem with that.

As they say, there's more than one way to skin a kat.

[KLC]

Yes I have only done overhead spraying with Forbid 4F and Sticker Spreader (Spreader Sticker?) to coat the leaves. Nothing fancy, no paranoia, no lost sleep. Most grew out of their ailments in a growing season.

I dont understand the coring. Are the mites only supposed to be in the core?

[Gee.S]

Yes I have only done overhead spraying with Forbid 4F and Sticker Spreader (Spreader Sticker?) to coat the leaves. Nothing fancy, no paranoia, no lost sleep. Most grew out of their ailments in a growing season.

I dont understand the coring. Are the mites only supposed to be in the core?

Yes, my understanding is that mites take up residence exclusively or almost exclusively in the core. That is way fresh leaves come pre-damaged. That is why translaminar miticides are required.

[Gee.S]

KLC, are you saying the coring method is unnecessary? You've had success just overhead spraying with miticide? Details please.

Many of us have knocked down mite infestations. I don't doubt for a second 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, by virtue of general health/condition. We have found in situ examples of apparent complete recovery from mite infestation, so Agaves do not appear to be entirely defenseless, Happy, healthy Agaves may manage to put up a better fight than those less suited to our garden environments.

I also find it likely that more than one type of Eriophyid mite is responsible for our woes pertinent to Agaves, and that subtly different strategies may be effective for different types. But this is all highly speculative, largely based upon scant anecdotal evidence. In the end, there is no advantage gained from such suspect insight, and the best means of addressing the issue is to wield your very largest hammer. Best to abandon any and all thought of a measured response, you'll need to hit 'em hard with everything you've got.

If Agave mite has entered your collection, and evidence of contamination is found on more than one plant, rotate your two miticides (three is preferable, but two should get the job done), spraying your entire collection top to bottom (but mostly the top) at 4-week intervals. You can skip spraying in winter months so long as lows go sub-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.

[bigdaddyscondition]

Good observations, all. Gee gives a reprise of a long and detailed discussion we had a few years back on the other forum, and it always helps to review the subject. As for "overhead spraying", spination, I don't use it so much as a term of art as simply repeating Matt's usage from his article. He also refers to "sprench[ing]", which sounds a lot like your stated method of basically drowning the plant, liberally soaking every accessible surface with the miticide spray. That's what I do, too.

Matt's article addresses much more than simply the coring method. He talks about host factors, general plant health, and cultural and physical controls on mite infestation, not to mention a brief discussion of eriophyid mites. They do concentrate in the newer leaves, the center of the plant called the apical meristem. They "do not burrow into the tissue, but feed on cell contents from the surface." There are many more gems in the article, and I recommend it as an excellent overview of the subject.

[Gee.S]

^ Don't spray too liberally. You can damage Agaves by allowing translaminars to pool/puddle on top. Plants treated with repeated applications of tranlaminars may produce deformed leaves, and puddling of these chemicals can cause immature leaves within the core to fuse, requiring physical intervention with sharp cutting tools.

[Stone Jaguar]

Overuse of surfactants/spreader-stickers also not such a good idea with many plants. Definitely contraindicated to use them with some products. When it's not expected to rain, I forego its use.

BTW, for readers with large gardens and/or collections, I would highly recommend the investment in a 4 gl/15 lt battery-operated backpack sprayer. They make life so much easier for gardeners! I had two in Guat...see Chapin offers one on Amazon for 135 bucks.

J

[Gee.S]

^ Yes, excellent point.

[Viegener]

I've had the Chapin 20000 1 gallon plastic sprayer for years, It's a great find on Amazon for $13.

[Azuleja]

Reading the the actual label for each product is absolutely mandatory. Some are very specific. Movento for example has a longer residual effect if applied with a spreader. The spreader cannot include a sticker.

[Viegener]

bigdaddyscondition or anyone else: is there a link to Matt Maggio's management method? Do you mean Maggio's "Operation Agave Might!: Combating Eriophyoid mite of Agave" from Cactus and Succulent Journal 84(6) in 2012? Anyone have a pdf??

[bigdaddyscondition]

Viegener, yes, that's the article (see my citation in the OP). The only way I could track it down was by emailing the Cactus and Succulent Society of America's business manager, Gunnar Eisel. I sent him a check for $7.00 and he mailed me the entire November-December 2012 issue.

Maybe the single article is available in PDF by now, if you're lucky. You can email Gunnar Eisel at geisel@citruscollege.edu. All this was the case in January 2013; it may have changed. If you can't find it this way you can inquire directly to the editor (Tim Harvey in 2013) at CSSJ_Editor@hotmail.com. Matt Maggio's email address listed in that issue was cactusmatt@yahoo.com. Good luck.

[mcvansoest]

I wish I could help, but I only have the back issues of the journal on DVD up to 1993. When I got those the later years were not yet available. There is a new volume on DVD now but that only goes up to 2003. Later issues are on sale for $8.00 an issue on the CSSA website.

[OWgave]

I know this post is 5 years old, but does anyone know where I can view Mr. Maggio’s article on combating mites for free? I would love to read it. All I can find is where it is offered on Bio-one for $10.

Thank you,
OWgave

[Gee.S]

You'll find a reference to it in my article on agave mite, available for download on this very forum. Two or three posts above yours also provide that information.

[OWgave]

You'll find a reference to it in my article on agave mite, available for download on this very forum. Two or three posts above yours also provide that information.

Thanks for pointing those out

Good Growing,
OWgave