[ Lost in the Landscape ]

exotic plant, exotic pest

I’m heart­bro­ken that one of the two big tree aloe in the front yard is under attack by aloe mites, the scourge of many aloe grow­ers. The suc­cu­lent expert at one of my local nurs­eries just shook his head when I asked for any­thing that would make the mites go away. Of course I ran to the web for advice. Dis­cus­sions splat­tered all over the charts, from guard­edly opti­mistic to “throw the thing in the trash.” I started to uncover sev­eral ref­er­ences to the syn­drome that the aloe gall mites gen­er­ate as “aloe cancer.”

The best dis­cus­sion I encoun­tered I’ve seen so far is at Xeric­World forums, where the whole range of opin­ions gets expressed by a num­ber of experts. The thread has lots of pho­tos of infected plants and of the mites them­selves. Grow­ers expressed suc­cess with insec­ti­cides (even though mites aren’t insects). Oth­ers had zero results even with ded­i­cated miti­cides. Most peo­ple rec­om­mend plant-surgery, and one per­son treated affected areas with bleach.

Sun­bird Aloes, a com­mer­cial firm in South Africa, the land of aloes, rec­om­mends a com­pletely dif­fer­ent treat­ment: formalde­hyde applied to the gall.

There’s also an infor­ma­tive page hosted by Michael J. Green hosted at the Gates Cac­tus & Suc­cu­lent Soci­ety [ here ]. The author here points out that the gall is pro­duced by the plant in reac­tion to a chem­i­cal pro­duced by the mites, a com­pound sim­i­lar to 2–4-d, one of the main ingre­di­ents in the infa­mous Viet­nam War her­bi­cide Agent Orange.

Most of the treat­ments are intended for spot treat­ments when only part of the plant is infested. But my poor plant has a major infes­ta­tion all over its main trunk, and that’s been affect­ing the growths far­ther up. It’s been in grad­ual decline for sev­eral years, but it’s going down­hill quickly. At first I thought it was gophers eat­ing the roots, or the renters next door stop­ping water­ing of their lawn and the aloe roots that extend under it. But I’ve finally fig­ured out the awful truth. Even the plant seems to real­ize its dis­tress since it’s start­ing to shoot new growths from near the base of the trunk.

I step back and try to be philo­soph­i­cal and maybe even mar­vel in my grief that such tiny, nearly microsopic crea­tures can take down such a large plant. It’s all a part of the cycle of life that we cel­e­brate with the sea­sons and the changes plants go through. Only with some­thing tree-sized I was hop­ing for some­thing that would out­live me, not a twenty-year rela­tion­ship that would end in tragedy.

If any of you have had luck with some­thing let me know! In the mean­time I’m try­ing a few treat­ments. As much as I try to avoid chem­i­cal nas­ti­ness in the gar­den, I’m des­per­ate. I’m remov­ing the galls and swab­bing the infected area with a 50% bleach solu­tion. I’ve applied the sys­temic insec­ti­cide imi­da­clo­prid at the roots, hop­ing that the insec­ti­cide won’t affect the ben­e­fi­cial bugs feed­ing on the plants nearby. Then I tried to spray just the affected plant–a big 12–16 footer–as best as I could with Bayer 3-in-1, which in addi­tion to imi­da­clo­prid con­tains the miti­cide tau-fluvalinate. I don’t know that these treat­ments will do any­thing other than relieve me of guilt that I didn’t try what I could to save the plant.

Wish me luck.

July 26 2010 06:30 am | Categories: gardening • my garden | Tags: Aloe bainesii • Aloe barberae • aloe mite • aloes

12 Responses to “exotic plant, exotic pest”

1. Pam/Digging on 26 Jul 2010 at 8:57 am #

   I’m sorry for your aloe trou­ble. We in Austin are fac­ing a scourge of agave wee­vils tak­ing out our biggest agaves. It’s heart­break­ing to lose a plant like that.

2. Loree on 26 Jul 2010 at 11:39 am #

   I am so sorry to hear about this! My only idea is to con­tact the fel­lows at Cac­tus Jun­gle. They may have an idea…http://www.cactusjungle.com/blog/

3. Noelle / azplantlady on 26 Jul 2010 at 3:47 pm #

   Oh, it can be so frus­trat­ing to deal with a pest that has no proven way to erad­i­cate it. Your tree aloes are so majes­tic and it hurts me to see them suf­fer. I wish I had some advice, but I do not…just know that I empathize

4. ryan on 26 Jul 2010 at 5:32 pm #

   Good luck. Tree aloes are really cool. I hope it at least doesn’t spread to the other one.

5. Candy "Sweetstuff" Suter on 26 Jul 2010 at 11:18 pm #

   Good luck to you. You are doing a valiant effort to health your aloe! I hope that your efforts are successful.

6. ricki - sprig to twig on 27 Jul 2010 at 12:49 pm #

   I won­der if cli­mate change is bring­ing on all man­ner of new phe­nom­ena and we are just begin­ning to see the tip of the ice (melt­ing) berg. Sorry, that was the oppo­site of helpful,wasn’t it? I do wish you well in your cam­paign to save your fab­u­lous tree, but more I can­not offer.

7. lostlandscape on 27 Jul 2010 at 8:34 pm #

   Pam, thanks for the con­cern. I know you have some spe­cial agaves, and hope­fully they don’t attract the atten­tion of the weevils.

   Loree, thanks for the rec­om­men­da­tion. I’ll see if they have any ideas.

   Noelle, I appre­ci­ate the com­mis­er­a­tion! Even our native plants are going through var­i­ous blights–borers in our oaks, for example.

   Ryan, that’s my main worry right now. The two plants touch in a spot and I’m watch­ing that area closely. And then there’s another huge mound of aloe only 3 more feet away. I hope I don’t lose the dra­matic struc­ture of the gar­den with the loss of three plants of this genus.

   Candy, thank you. I’m keep­ing my fin­gers crossed too.

   Ricki, there’s a lot of truth in what you say. This par­tic­u­lar mite sup­pos­edly is lim­ited by cold weather, but it’s been many years since we dipped below freez­ing longer than to put a light glaze on the car windows.

8. tina on 03 Aug 2010 at 4:59 am #

   I wish you much luck. It is awful to sit back and feel help­less when one of your prized plants is dying. Let us know how it goes. Good lcuk!

9. Christine on 03 Aug 2010 at 7:04 am #

   Oh no, how heart­break­ing. I find that when plants are afflicted by a pest, it’s usu­ally because there were other stres­sors involved that drew the mites to the plant in the first place. It’s rare to see a healthy plant com­pletely taken down by one attacker, so maybe it was affected by less water from the neighbor’s lawn, etc? Sorry, that’s not really com­fort­ing, but at least you know that you’ve done every­thing you pos­si­bly could, includ­ing going against your organic pref­er­ences (which I think really shows you care!)

10. Daniel on 04 Jul 2011 at 11:20 am #

    Hello,
    I have recently fallen for the majes­tic beauty of the cacti/succulent world. I planted a 12ft Bar­berae less than a cou­ple of months ago and can­not stand the thought of a virus affect­ing its health and beauty. It has been a year since this post. How are your plants doing?

    ;(

11. James on 08 Jul 2011 at 4:56 pm #

    Daniel, the news isn’t good, and I’ll be doing a fol­lowup. The aloe mite was an issue, but I’m think­ing that the worse prob­lem in this case was gophers chew­ing on the aloe’s roots. The nearby smaller bar­berae looks just fine–no mites to speak of, while the larger one is just about gone. Good luck with yours!

12. [ Lost in the Landscape ] » random updates on 15 Jul 2011 at 1:24 pm #

    […] Update #3: Aloe, good-bye (Orig­i­nal post: Exotic plant, exotic pest) […]

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