Today I noticed something strange on my Obregonia, a section of discolored tubercles.
At first I thought it was rot, it had been quite rainy the past week but it's tolerated worse weather before.
The tubercles were black but didn't seem like rot, they were still pretty sturdy though they felt dehydrated.
So I removed them but the tissue underneath was also black. It wasn't mushy or particularly moist like rot, it didn't have a foul smell either and the rest of the plant looked fine aside from a few root mealybugs.
Any help is appreciated thanks
IMG20221222110347~2_copy_948x924.jpg (91.23 KiB) Viewed 1307 times
It looks like a root mealybug. It should not have caused much damage to plants. So far.
However, the soil in your flowerpot is useless. I suggest that you completely replace it. Then the root of the plant must be thoroughly cleaned and allowed to dry for a period of time before being replanted into new flower soil.
This is my personal suggestion. Listen to what others say.
Salazar wrote: ↑Thu Dec 22, 2022 5:10 pm
Today I noticed something strange on my Obregonia, a section of discolored tubercles.
At first I thought it was rot, it had been quite rainy the past week but it's tolerated worse weather before.
The tubercles were black but didn't seem like rot, they were still pretty sturdy though they felt dehydrated.
So I removed them but the tissue underneath was also black. It wasn't mushy or particularly moist like rot, it didn't have a foul smell either and the rest of the plant looked fine aside from a few root mealybugs.
Any help is appreciated thanks
Root mealies weaken the entire plant, although I do agree with Aztekium 123 -- I believe they aren't the main problem.
A basic rule of thumb that applies to growing desert cacti -- for good or ill, everything starts out in the roots. Please give me the details on what you have in your mix. Ingredients and proportions of each should tell us if your Obregonia is or isn't growing in a mix that's right for the plant.
If you just want photos without all the blather, please visit my Flickr gallery.
My location: Los Angeles, CA (Zone 10b)
The root mealybugs I saw were very few in number, I've had much worse infestations before, it's around this time of year when I notice them starting to make their presence known.
Well I don't have exact numbers for proportions but it's nearly purely inorganic material, volcanic rocks, pumice, quartz and silica granules and a tiny bit of garden soil.
Salazar wrote: ↑Fri Dec 23, 2022 7:29 amWell I don't have exact numbers for proportions but it's nearly purely inorganic material, volcanic rocks, pumice, quartz and silica granules and a tiny bit of garden soil.
Good -- contrary to what Aztekium123 said, there's nothing wrong with your mix. Root mealies tend to show up in the winter, although I used to think it was a problem confined to temperate and cold winter climates -- interesting to know that root mealies can get active in tropical winters too. Imidacloprid soil soaks are a highly effective way to get rid of mealy and armored scale infestations, but I have a feeling that you're not allowed access to it in the Philippines.
One other thing we'll want to look at is fertilizer. If you haven't seen this before, here's something for you to consider:
When it comes to good cactus growing, not all fertilizers are equal. If you "compare notes" and find that your fert doesn't stack up well against what I'm discussing in my presentation, hopefully it'll give you some useful ideas.
If you just want photos without all the blather, please visit my Flickr gallery.
My location: Los Angeles, CA (Zone 10b)
Yeah root mealybugs have kinda always been present in my collection, some plants are definitely affected more than others. Mostly their numbers are low enough that it's not much of a bother to the plants. Mostly it's the Astrophytums that are hit the hardest especially this time of year.
I don't really fertilize a lot. I'll occasionally put in a few pellets of a slow release fertilizer if I have it on hand, that's it.
Salazar wrote: ↑Sat Dec 24, 2022 12:04 amI don't really fertilize a lot. I'll occasionally put in a few pellets of a slow release fertilizer if I have it on hand, that's it.
That's a problem. I've been growing the vast majority of my cacti in a soil-less 60% pumice/40% granite gravel mix for over 10 years. This is an essentially hydroponic approach, so I have to fertilize every time I water the collection during the spring-summer growing season here in SoCal. I only use 2 liquid fert concentrates in my watering solution -- if you read my presentation in the above link, you'll get all of the details on what I'm doing and why I'm doing it. A slow-release fert may be fine, although I have no experience with them. If I did, this is the only one I would use:
Unfortunately not available in the US, and shipping from Australia would be cost-prohibitive for me. Maybe not as bad for you, and if you don't want to go to the trouble of using a liquid fert, the Osmocote MikeInOz is recommending should be perfect.
If you just want photos without all the blather, please visit my Flickr gallery.
My location: Los Angeles, CA (Zone 10b)
Salazar wrote: ↑Sat Dec 24, 2022 3:00 amI'll definitely try if I can get some of your recommended fertilizer and pesticide.
It is not important to get exactly Dyna-Gro. It is the ratio of the fertilizer components that you are trying to match. Mike in Oz showed an Osmocote product he is able to get in Australia that works well for him. You will have to see what is available in your country. You will also need to know what the regulations are regarding how a fertilizer label has to report the concentrations of the fertilizer.
Jerry Smith
Bloomingdale, NJ
45 inches (114 cm) rain equivalent per year, approx. evenly spread per month
2012 USDA Hardiness Zone 6b: -5F to OF (-20C to -18C) min.
Salazar wrote: ↑Sat Dec 24, 2022 3:00 am
Thanks again for the quick response
I'll definitely try if I can get some of your recommended fertilizer and pesticide.
So if my understanding is correct the black areas are an indirect symptom and not direct physical damage from the mealybugs.
So regarding the plant itself, what would you recommend to do?
Should I apply something to that area like peroxide perhaps or will a few days of air drying be sufficient?
Jerry makes a few good points regarding fertilizers, so I'll put some thought into the matter and see if I can give you a few choices based on what you can get in the Philippines. For now, here's what to do:
Soak the roots of your Obregonia in warm soapy water to kill the root mealies and their eggs. Theoretically, plain dish soap should be fine, although I'm leaning more toward an insecticidal soap if you can find it. Per one of Jerry's posts:
jerrytheplater wrote: ↑Sun Nov 06, 2022 1:13 amI had Root Mealy bugs in my cacti discovered in January, the heart of my winter. I took them all out to their pots and washed off all of the potting mix. I then soaked them in a 2% soap solution to which I added Malathion according to the label directions.
Malathion isn't required (you probably won't be able to get it anyway), so just go with his recommended 2% soap solution.
Let the roots dry out thoroughly. Soap residue will provide a layer of protection, so do not rinse it off before you repot.
Once you repot the plant, let its roots settle in for 2 weeks before you water.
A small cactus in a big pot never works, so I'd like to find out if you have a pot that's the right size for your Obregonia. Please give me the following dimensions:
Diameter of the base on the soil line here:
IMG20221222110347_2_copy_948x924.jpg (91.74 KiB) Viewed 1213 times
Length from the soil line to the lowest root.
Once I have those numbers, I can give you the correct diameter and depth for the pot you should have. If you already have the right pot size, excellent. I'm not seeing any black areas in your photo, so they may have been the tubercles you removed. What I'm more concerned about are the whitish patches and yellowing on some of the tubercles -- a clear sign of nutrient deficiency.
If you just want photos without all the blather, please visit my Flickr gallery.
My location: Los Angeles, CA (Zone 10b)
Salazar wrote: ↑Sun Dec 25, 2022 3:09 am
Apologies for the rather late response, Christmas and all that.
The diameter at soil line is ~2.5cm
The soil line to longest root is ~7cm
No worries. Here's a pot size range for you: Diameter = 5 - 6.5 cm., depth = 9.5 - 11 cm. If you have a pot in that size range, you're set. The only thing I should mention is this -- if your pot is ceramic, those numbers should be inside diameter and inside depth. If your pot is low-fired clay (in other words, terracotta), you'll be better off with a nonporous pot even if it's plastic. You'll find the reason why here:
Salazar wrote: ↑Sun Dec 25, 2022 8:15 amMerry Christmas to you too if you celebrate it
Indeed -- I'll be celebrating Christmas with my mother, brother, and his girlfriend, getting together with them later today. It's a hot, dry Christmas Day here in SoCal, but not unusual -- I've seen a fair number of them over the course of many years.
Since the Obregonia isn't your only cactus, the liquid fertilizers I have in mind should be great for your cacti and succulents. If you can't get the Osmocote slow release fert I mentioned in one of my earlier posts, I'll give you the details in a day or so.
If you just want photos without all the blather, please visit my Flickr gallery.
My location: Los Angeles, CA (Zone 10b)
