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  • From: jedd <jedd@progsoc.org>
  • To: permaculture@lists.ibiblio.org
  • Subject: Re: [permaculture] Using Prickly Pear cacti
  • Date: Mon, 14 Aug 2006 10:47:12 +1000

On Monday 14 August 2006 7:40 am, Lisa Rollens wrote:
] I have a pasture that is getting overtaken by prickly pear cactus.
] I understand bushhogging only makes it worse, and have seen that.
] So I need to dig some up, but would like to try using them. From
] Cornucopia II I see that the pads are good for human and livestock
] food/feed, but how does one actually prepare them? Has anyone
] actually done this and can pass on specific "how-to"s? I thought
] of holding them over a fire briefly to burn off the thorns....????

Hi Lisa,

I've heard you can apple-core the various spines on pads, and then
boil up for human consumption, or just feed to the livestock. This
seems a pretty intensive job, though, especially for a paddock-sized
collection of this weed. I've seen some pretty sparsely-thorned
pads on some of my plants, but most of them are well-blessed in the
thorn department. I've also had pads sit at the bottom of a 6-hour
bonfire, and still be green at the end of it - so they're pretty hardy
to fire - you wouldn't need to hold each pad over a fire.

In Australia, prickly pear was a significant pest in the early half of
last century -- it'd been introduced, I believe, as a drought-tolerant
feed source and hedgeable livestock-proof fence combined. In reality
it didn't work too well, and resulted in enormous areas of land being
overrun. It's one of our better moments in ag research/science - the
testing of the Cactoblastis moth and subsequent introduction of same
as a biological control. (Compare and contrast the introduction of
the cane toad - a prime swallow a spider story.)

Now, thank you for mentioning what country you're in - a lot of people
forget to do this. As I understand it, the cactoblastis moth is a
native South American animal, so I'd assume it would have been
present in your part of the world. Wikipedia implies that it isn't,
so it might not be an appropriate control mechanism in your area.
Apparently it attacks some other opuntia species -- not a problem for
us in Australia, but would be if you have native opuntias that you
don't want to feed to the moth.

The moth typically eats an amount of the plant, and then in the latter
stage of its life cycle, will fly around and find another plant to lay
its eggs in. This means that the infected plant doesn't necessarily
die, just gets knocked around a fair bit. The other biological control
we have here is for another nasty cactus (Tiger pear) - a far pricklier
beast that can puncture a car tyre. It was introduced here as a host
for the cochineal insect (used to produce red dye) a hundred years or
so ago -- and later that afternoon someone invented an artificial red
dye that was much cheaper than hunting around for 1mm long insects
to crush up. Insult to injury time, really, as we ended up with an
easily-spread, painful, dangerous, prickly cactus spread around the
countryside, that was totally unused, nay unusable.

I digress.

The cochineal beetle will almost definitely destroy the plant that it
is living in. Tiger pears tend to get maybe a metre across, but rarely
more than a half a metre high - so not on the same scale as prickly
pear. On the downside it just makes it easier to walk into a bed of
the things. Apparently the beetle will, once it's destroyed the host
plant, wander around looking for another plant - but it doesn't
wander very far, often giving up and going to ground for the winter.

So .. why mention all this? Well, the main biological control is
probably not in your area (you'd have noticed by now) and you may
well not be allowed to introduce it (but then again .. depends who else
is being affected, and what the trade-off really is). Another
potential biological control may be in your part of the world, but
might just need introducing onto your property. I'm not sure if the
cochineal bug will live in your particular Opuntia (note that there's
a few species under that genus, with varying fruit output) but if it
does, you may well be able to splinter into two sub-markets - tuna
fruit (in the short term) and 'safe' red dye in the longer term.

From a pragmatic point of view, I'm inclined to suggest that having
a lifestock feed that doesn't require human intervention would be a
preferred option. There are a number of drought-tolerant trees that
may be better suited for your animals. Dealing with prickly pear
is a very resource intensive pursuit.

Btw, what is bushhogging?

Jedd.




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