(Saguaro?) Cactus Pest/Fungal Issue #570650 - Ask Extension


(Saguaro?) Cactus Pest/Fungal Issue #570650

Asked June 15, 2019, 4:12 PM EDT

I've had this cactus for about 7 months now, and little smooth but hard, shell-like, scab-like spots appeared all over the plant, on smooth surfaces and in some of its crevices. I thought it was a scale insect, and from my research tried a variety of fixes - I used a q-tip with rubbing alcohol on the spots, then I used an anti-fungal spray for indoor plants, and then I went around and manually picked each piece off. Now all of those spots I picked off are turning into scars, but I've also noticed more of those spots appearing. I'm attaching pictures of the spots and what they look like after I take them off the plant. Previous spots were hard on the outside, and many of them had a brown, soft, dagger-type piece that came out of the plant. I didn't see that so much in this latest round. My question is... is there any way I can save my cactus? And are you able to identify what these spots are and how I could stop them from continuing to take over? Thank you!!

Hennepin County Minnesota

Expert Response

http://www.cactiguide.com/forum/viewtopic.php?t=40418 I visited a friend who has a large collection of cactus and she is sure the marks you are seeing are scabs too. Nothing needs to be done. Your cactus will need intense light so LED plant lights that deliver 6500K are recommended and saguaro need very little water.
Claire Kari Replied June 16, 2019, 9:05 PM EDT
Your cactus might also have scale, especially those rounded up things around the spine. Here are some ways to control it. With scale the scale does have to be crushed or smothered for treatment to be effective. https://www.sublimesucculents.com/how-to-treat-scale-on-your-succulents-and-cacti/
Claire Kari Replied June 17, 2019, 7:37 AM EDT

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