Friday, November 22, 2013

Public Service Announcement #6: Ants Attack Agave.

Bad News. 
But rare news its seems, thankfully; no-one seems to have heard of this, which excites the mission of this blog- to document new things in this universally-widening but often redundant internet.

Extra! Extra! Ants Attacking Agave:

This is either Agave parryi or A. p. neomexicana- I forget- but the bases of its leaves are being consumed by "Pavement Ants" (perhaps Tetramorium caespitosum) under a protective shell of glued-together dirt bits, which they will do when they are ranching aphids on the base of a plant, like strawberries.  I have brushed this shell off a bit to reveal their dirty work! 

Dirt-awning intact.  Seeing this on a plant disturbs me. It always means going to war with friends, a war which generally doesn't really end, but ebb and flow.

The story and my working theory are this:  This Agave is not the only plant being eaten; they are otherwise exemplary newly established plants in a prvate home landscape I made this year in Grand Junction.  A Few months after planting, the plants all grew phenomenally after the monsoon rains, and this is when a Globemallow died out. Upon closer inspection, it had been "girdled" by ants, who had built their dirt-shed around the base of the plant and removed the joicy outer lay of the stems of Sphaeralcea grossularifolia (Globe Mallow), Hymenoxys/Tetraneuris/Haplopappus scaposa (Sunshine Daisy/ Perky-Sue),  Desert four-o-clock (Mirabilis multiflora) and Calylophus hartwegii var. fendleri (Fendler's Sundrops.)   They have so far not touched Prairie Zinnia (Zinnia gradifora), Mohave Sage (Salvia dorrii), Claret Cups (Echinocereus triglochidiatus/mojavensis) nor Saltbush (Atriplex confertifolia)

The landscape has been organic (in the popular sense) so far and has "sustainability" written all over its insides, so I tried "natural" methods: garlic and pepper powders.  The ants, I thnk, rubbed their jointed limbs together and said "Oh, we love Itialian!" and chowed down again.  I tried Cayenne pepper. The bits that did not wash away in the rain were ignored by the ants.  Who kept eating.  I was out of town to re-apply, so the client dumped a fat heap of it down into the rosette, and what appears to have actually stopped the ants was that the rain-wet Cayenne pepper became a hard cake physically keeping them from getting down into it again.  Alas.

My theory is this.  It's pretty weak. Once upon an April, this landscape was short-mowed bermudagrass and weeds, (mostly Kochia and Purslane), and the ants were living there sustaining themselves for years on the mini-ecology of weed parts and bugs that eat the weeds.  This summer, some clever dick with a pickaxe came in, removed the bermuda sod, weeds, most organic material (including surface weeds seeds) , added a thin layer of compost, and a thick layer of pea gravel dotted with native plants.  A real moonscape compared to the dusty jungle of weedy turf the ants had built their empire in.
Having had everything taken away, a sizable population of ants underground became more desperate than normal, forcing them to acquire new tastes, or die.  
 The End.

With the ants brushed away, too, the poor plant's fibers are exposed. This was early on and they returned several times to make it much worse.  I hope it survives the winter.

If you, too have ever seen this, please share, as it seems pretty undocumented.


Susan in the Pink Hat said...

I have the exact same situation going on with an E. triglochidiatus. I put out an ant bait-thingy, which they ignored. The cactus appears to be fighting back by pushing out a lot of new buds. We'll see who wins.

I remember Bob Nold saying something about adding too much sand during transplanting can attract ants. Maybe easier digging than larger squeegees?

Kenton J. Seth said...

Susan; how wild!

A friend, upon my presenting this to his expertise, told me about a trigloch he had which was rotting at the base from potato soft-rot (Erwinia) when the ants came along and ate it clean, and the cactus, hovering decapitated, callused and began to re-root downward through its old base-husk like a freak stem-cutting.

There is no sand at all here- I bareroot plant. I don't believe that sand... "attracts" (to be anti-anthropomorphic) ants as much as ants prefer and prosper in warm, dry soils. Sand tends to be drier, relatively. Under stones is warm, too… So sand-beded flagstone and pavers are rich places for ants, no? 

Ants have prospered on the South face of my sand-between-sandstone desert crevice garden. Above the ground level, it is quite dry. They have not attacked plants directly, but have buried plants and excaved around young ones, which dried them out to death. When they tunnel too close to my more precious plants, I flood or collapse their hole. They are allowed a few good spaces where I don't want plants anyhow. We are approaching a truce.

Do update us on what happens with your claret cup. (Susan, you are near John Stireman, who's mentioned on this blog. Do you know him or have you seen his garden?)

Susan in the Pink Hat said...

I will keep you posted on the cacti. It seemed okay this season; we'll see what spring brings. I also have an ant colony in my compost heap, which makes for difficult turning. I do know the Stiremans as I am in WRGS and have been to both his and Patrick's gardens on the annual tours. Truly, the best of the best.