[Arid_gardener] white spots on prickly pear cactus
JanetH at dprinc.com
Mon Aug 28 09:14:13 MST 2006
donmar5 at cox.net
I have a fairly young prickley pear cactus and it is getting covered
with spots of a white, soft, sticky substance. I see it on many of this
type of cactus in my neighborhood, Is this a natural occurence or is it
a disease? How can I stop it?
Don, what your cactus is experiencing is actually an insect -- it's
called cochineal scale. It's a naturally occurring infestation of this
insect, my experience is that some types of cactus are more prone to it
than others. I have a number of different types of prickly pear, some
that don't seem to be bothered by it, others that it seems to attract.
Cochineal scale has been gathered by Native Americans for centuries, and
is used to make red dye. If you press on the white substance, you'll
squish the bug and a bright, intense red will appear -- collect enough
of it and you have a natural dye. I'm guessing that's not what you want
Cochneal scale, left unattended can eventually adversely affect your
The good new is that if your plant hasn't been infested for an extended
period of time, it is treatable and your cactus should do just fine.
The best way to treat that I've found is to spray the plant with soapy
water, then follow with a blast of spray from a garden hose.
Mix soapy water mixture at a ratio of 1 gallon of water to 1 tablespoon
of soap (I've found liquid Ivory works great). Place in a spray bottle
and spray the entire plant thoroughly. You'll notice as you spray that
the white, sticky substance begins to dissolve and you'll actually be
able to see the little black insect beneath. Once I've sprayed the
entire plant thoroughly with the soap mixtre (concentrate on the
undersides of the pads, and where the pads attach), I wait 10-15
minutes, then follow up with a good blast of spray from the garden hose.
This will knock off most of the scale.
I've found that I need to keep a close eye out, and repeat as often as
necessary to keep the scale under control. Good luck with your cactus!
Master Gardener volunteer
University of Arizona Cooperative Extension
More information about the Arid_gardener