Anodyne Posted February 25, 2014 Can anyone help ID this problem? The growing tips on a TBM and one other bridgesii are affected, but dozens of others growing next to them in the same conditions are not. I found one picture which seemed to match, but they couldn't ID the problem either. No pests that I can see, has something gotten into the soil maybe? Or is it a deficiency? Or disease? Help my cactus please! Share this post Link to post Share on other sites
Evil Genius Posted February 25, 2014 It´s mostly on new growth. I guess it´s because there aren´t enough nutrients for a proper chlorophyll production. Don't think it´s viral. Would repot. Share this post Link to post Share on other sites
Pie'oh'Pah Posted February 25, 2014 Could it be Phototoxicity, have you used any chemicals recently? Share this post Link to post Share on other sites
Anodyne Posted February 25, 2014 Yes, it's only on the new growth but is spreading fast. A few days ago it was only on one TBM pup (the one pictured) but now at least 3 others are starting to show the same thing. They have been fed regularly (dilute soluble fert), but they are growing quickly at the moment so I guess deficiency would fit. I'll repot asap and see how they go. Maybe toss the soil just to be safe. PoP, no I haven't sprayed them with anything. Share this post Link to post Share on other sites
Swiper Posted February 25, 2014 Sunburn ? ..... have got similar on my TBMs (in full sun) which appeared after hot sunny days, moved one out of the full sun into 50 % sun it looks much better now. Are yours in full sun ? 1 Share this post Link to post Share on other sites
Evil Genius Posted February 25, 2014 Check for Root mealies and Spidermites. They sometimes cause this too. Share this post Link to post Share on other sites
Anodyne Posted February 25, 2014 Yes, they're in full sun and have been for a while. Could you post a pic of yours Swiper? This doesn't look like any sunburn I have seen before. It looks as EG said, that some of the cells in the new growth aren't producing chlorophyll for some reason. But unlike healthy variegation, this tissue looks sort of pithy underneath the skin, like the cells are just empty or something? The areas don't seem damaged or feel soft, but they can't be healthy! Thanks for the tips Evil Genius, I will quarantine the plants for now and check the roots when I repot. 1 Share this post Link to post Share on other sites
AndyAmine. Posted February 25, 2014 Im getting the same thing the last few weeks, from my limited observation it seems to come up after a chemical fert feed on a hot/sunny day or when the sun moves position and hits the plant from a different angle. 1 Share this post Link to post Share on other sites
Anodyne Posted February 25, 2014 Yeah, that could be it too. They've been in full sun for months, but I did shuffle them around recently and they get regular dilute feeding. So...what do you reckon? Repot, move to a shadier spot, and a little food in case it's just a nutrient deficiency? Or should that be no food, in case that the problem?! Argh! Share this post Link to post Share on other sites
AndyAmine. Posted February 25, 2014 (edited) Personally, I would give them a good flush with water containing a very small dose of ferts in it so that the salts have something to grab on to incase you're getting salt lockout.That way you know you are starting with a clean slate, Then give them a good whack of seasol as a tonic and put them in a shadier spot.If the spots get worse then you can assume its a deficiency and give them a feed with 1/4 strength of your regular ferts, and see what happens, if things look better after a week or so then slowly increase the dose back up to what you are used to. If it keeps getting worse then it would suggest something else, perhaps pests like gnats/mealy or disease?Sorry if that isnt very clear, its late Edited February 25, 2014 by AndyAmine. 1 Share this post Link to post Share on other sites
Anodyne Posted February 25, 2014 Perfectly clear, thankyou for the suggestions! 1 Share this post Link to post Share on other sites
Hellonasty Posted February 26, 2014 Hey everyone, Sorry to throw a spanner in the works but I believe this damage is caused by scale, which are a sucking insect, if you look closely at the first picture there are two brown scale visible. The one at the 5 O'clock position is just below a sunken/damaged area, they move similar to a snail, they eat/suck and then move on to a new section of the skin, they move slowly. They like the new growth because it is softer and easier for them to damage. Use your fingernail or similar sharp tool and scrape the skin, it is difficult but you will cause the scale to fall off and you can inspect it. There are variety of treatment methods for scale. Share this post Link to post Share on other sites
Anodyne Posted February 26, 2014 Those are not scale I don't think. That was my first thought too when I saw them. But I have examined them closely and they do not scratch off. Pretty sure they were just little puncture wounds from being jostled against other cacti's spines, that have then scarred up, perhaps with tiny tiny patches of black rot underneath. Sorry I couldn't get better photos, I am waiting on delivery of a new macro lens, but honestly those photos are pretty close to what I can see with my naked eye. Well spotted! Share this post Link to post Share on other sites
theuserformallyknownasd00d Posted February 26, 2014 Yeh I'd have to say bug damage also based on the pictures, but also my tbm collection did the same when I didn't water them we'll enough before a week of hot weather... Agh gotta love plants! Share this post Link to post Share on other sites
Anodyne Posted February 26, 2014 The salt lockout thing makes good sense. I always try to water in the evening to avoid sunburn, but I have fed them once or twice during the day, and these are hot days. Dammit, I even knew that salt crystallisation was a risk, and especially so with the terracotta pots they're in. I'd just never seen the results before, so I didn't make the link. I've flushed the pots well, and hopefully this rain will finish the job for me. I'll repot into plastic asap and check for subterranean critters at the same time. 1 Share this post Link to post Share on other sites
zelly Posted March 1, 2014 do you guys ever wonder about how plants might react to abnormally high uv radiation particularly after an abnormally large CME? why some tips & not others? Maybe it only affects new tip growth. Not much in the news about CME's unless you follow such stuff. Share this post Link to post Share on other sites
theuserformallyknownasd00d Posted March 1, 2014 +1 for Zelly! Share this post Link to post Share on other sites
Swiper Posted March 2, 2014 I went to check the TBM's and noticed most of the white spots have disappeared. The first pic shows the sunburn scars at the rear and the remains of the white spots on the front pup. This has been moved to 50 % sun. The second TBM is still in full sun , small marks remaining. 1 Share this post Link to post Share on other sites
Anodyne Posted March 8, 2014 (edited) The TBM seems to be doing better in a shadier position and after flushing the pot well. Here are the before and after photos: The other one still looks sad, and the white patches seem to be a bit sunken now as well. Today was the first clear day, so I got out and repotted it. No sign of any beasties anywhere, but there were visible salt crusts on every surface: the inside of the pot, around the drainage holes, even on the base of the stem. I washed the roots and replaced the soil, will see if that helps. I knocked together a worm farm too - no more salt ferts for the cactus! Edited March 8, 2014 by Anodyne 1 Share this post Link to post Share on other sites
Maxuel Powers III Posted March 11, 2014 Looks like classic sunburn to me. Share this post Link to post Share on other sites
