Q. I appear to have a
massive infestation of Cottony Cochineal Scale on my prickly pear cactus. I can
usually get most of it off by hosing, but much is hard to reach. Beyond hosing,
what insecticide or other kind of solutions do you recommend? Permanent, if
possible!
massive infestation of Cottony Cochineal Scale on my prickly pear cactus. I can
usually get most of it off by hosing, but much is hard to reach. Beyond hosing,
what insecticide or other kind of solutions do you recommend? Permanent, if
possible!
A. Yes, scale is quite
common on cacti in general and prickly pear in particular. This one in particular is most likely cochineal scale rather than cottony cushion scale. This cochineal scale is a close relative of the cochineal scale that was used by the Spaniards in Mexico centuries ago and die making. This scale leaves a purple color on your finger when you rub it.They can be hosed
off the pads with a strong stream of water as you are doing but they reinfest
the pads very quickly and in full force again in a week or two.
common on cacti in general and prickly pear in particular. This one in particular is most likely cochineal scale rather than cottony cushion scale. This cochineal scale is a close relative of the cochineal scale that was used by the Spaniards in Mexico centuries ago and die making. This scale leaves a purple color on your finger when you rub it.They can be hosed
off the pads with a strong stream of water as you are doing but they reinfest
the pads very quickly and in full force again in a week or two.
When I am growing prickly pear as a food I am more
concerned with insecticides and getting them into the food we eat but if they
are grown just as an ornamental plant and not used for food then I feel better
about using something stronger than water, soap and water sprays.
concerned with insecticides and getting them into the food we eat but if they
are grown just as an ornamental plant and not used for food then I feel better
about using something stronger than water, soap and water sprays.
The problem with a strong stream of water is that the
force from this water is not enough to knock the insect off of the pad, only
the white, fluffy coating surrounding the insect. So it is a short time before it
regrows this protective cover and the unsightly mass of cotton is back again.
force from this water is not enough to knock the insect off of the pad, only
the white, fluffy coating surrounding the insect. So it is a short time before it
regrows this protective cover and the unsightly mass of cotton is back again.
Knocking the fluffy covering off first with a strong
stream of water will make these insects more susceptible to an insecticide
spray. Most of the common insecticides will work after that; malathion,
pyrethrins, Sevin, just about any common insecticide will work after the fluffy
covering has been removed. This does not mean they won’t be back. They will.
But it will take longer for them to get established on the plant again.
stream of water will make these insects more susceptible to an insecticide
spray. Most of the common insecticides will work after that; malathion,
pyrethrins, Sevin, just about any common insecticide will work after the fluffy
covering has been removed. This does not mean they won’t be back. They will.
But it will take longer for them to get established on the plant again.