We Get Questions – Ian's Edition
I purchased these a little over a year ago from your Cactus Jungle. They seemed to be doing well, then suddenly developed this white substance at the end of the spines. At first it was just on the larger “barrel” cactus, but now it is on one of the smaller ones, too. Also, one of the smaller ones “shrunk” into the rocks. I see the white substance also on the flesh of the cactus. The spines come out easily and it seems to be shrinking. Do you have a diagnosis? What treatment, if any?
Thank you very much for your help. I really enjoy these cacti and want them to survive.
Nancy, it appears that your cactus have spine-mealy bugs. They can be treated with a paintbrush and rubbing alcohol and a treating with neem oil.
The cactus that shrunk into the soil appears to have passed on.
If you can bring them down to us we’d be able to treat them and figure out more definitively what’s going on.
More from Ian after the break…
The spine mealy bugs can be a little stubborn, so a ‘firm’ paintbrush is recommended in conjunction with the alcohol. Maybe even tweezers. They have likely (gauging from the amount in the pictures) moved into the soil as well.
After initially treating with the alcohol on a paintbrush you’ll want to spray the plant, as well as drench the soil, with a neem solution. Continue to treat with neem once every week or two for at least a month or two.
Just make sure that when you apply the neem, keep the plants out of direct sunlight for a day, as the oil will magnify the sun’s rays and burn the plants.