Ethnobotanicals Cacti Garden Pest Infestation

[G_Chem]

Fuck me guys… I listened to the some “expert” online and yesterday cuz of her I had to cut two of my newest cacti.

All started with these little black dots on the newest growth of one cutting. I thought maybe overwatering but quickly it spread, along with a light cob webby like substance in the infected areas.

I also saw what looked like little reddish brownish bugs (not spider mites, longer bodies more akin to an earwig, but too small to see well) as well as what appeared to be fungus gnats flying around.

I wasn’t quite sure what was the problem as I didn’t think those little bugs were fungus gnat larvae but saw an article that claimed many pests could be got rid of with isopropyl alcohol in a spray bottle.

The gal even swore she “soaked” some succulents for days no problem.

Well I sprayed my cacti then left for a couple weeks, I come back and half of them now had purple spots with the worst effect being squishy from rot. The two new bridgesii had to be cut back to stumps in hopes they’ll survive.

The infestation looked better but not perfect, but the damage done not worth the outcome.

I think my others, although damaged, will survive. But would like any input from growers better than I on what to do next. I still have an infestation that will grow if not treated but isopropyl scares me to use again. Thanks!!

-GC

 

[darvocet21]

This woman probably sprays Roundup on her vegetable Garden. She's an idiot. Unfortunately more and more idiots are allowed on radio and TV. No that's not right: to get on radio or television as any kind of an expert you have to be an idiot. That was passed with bipartisan support.

 

[G_Chem]

So I think I was able to salvage most of them, and the ones that got the worst of it got cut back which I think saved them.

But yea I’m tempted to contact her or the company I buy from to bitch, she just killed like 60-70$ worth of cutting.

I’ll report back once I finish off these pests. Wonder if a dilute h2o2 solution would work? Just how dilute…

-GC

 

[darvocet21]

Good luck! I wouldn't use any chemicals harsher than liquid soap (ideally Dr. Bronner's, but dish soap is OK) one drop in a quart of water put into a spray bottle.. enough to desiccate the suckers

 

[G_Chem]

Good idea, I’ll try some Bronners.

-GC

 

[bmmjb]

Do you have a photo? My Bridgesii often develop black spots. If they are otherwise healthy, they grow out of it. I have some in pots and some prized plants in the ground for 20 plus years.

Iso is not something I've heard of. I am a lifelong gardener, with veggies, fruit trees, and lots of flowers in my garden. Black fungus, if it gets out of hand, usually needs to be cut off.

How old or large are these? Good old fashioned Bordeaux mix, half strength at most, usually stop fungus, and horticultural soap will usually kill any bugs it contacts.

Also, indoors or outdoors makes a difference. Cuttings like to be really dry for a very long time, as in months, until they become established.

I have some other thoughts as well, but need more info. I really like my cactus.

 

[G_Chem]

Na no photos. I know the black spots you speak of which are typically when they get a little too much water they start to “bleed” and those scab in these little black dots.

This was similar except all concentrated at the top new growth, and many more than normal all close together. The tiny bugs and tiny light cobwebs also told me had to be a pest.

They vary in age, but some of these I’ve had about 10yrs. The newest ones took the worst hit.

I’ll try the soap idea to see if I can’t finish the little guys off.

-GC

 

[G_Chem]

Infestation isn’t gone.

Today I looked them over and saw some of the bugs so took a magnifying lens to them but still couldn’t really make them out, they’re that small.

So I squished one with a Q-tip and put under a microscope to see better. At 100x I was able to make out a bug that somewhat resembles a long fly, it had somewhat short segmented antennas, and what appeared to wings. Yet these things aren’t flying away which makes me wonder, are these fungus gnat larvae?

I do still see gnats flying around a tiny bit which has me wonder if these things eating my cacti are some early stage before they can fly.

Any help would be appreciated, I’m scared to spray them with anything else right now..

-GC

 

[F.U.B.A.R.]

Infestation isn’t gone.

Today I looked them over and saw some of the bugs so took a magnifying lens to them but still couldn’t really make them out, they’re that small.

So I squished one with a Q-tip and put under a microscope to see better. At 100x I was able to make out a bug that somewhat resembles a long fly, it had somewhat short segmented antennas, and what appeared to wings. Yet these things aren’t flying away which makes me wonder, are these fungus gnat larvae?

I do still see gnats flying around a tiny bit which has me wonder if these things eating my cacti are some early stage before they can fly.

Any help would be appreciated, I’m scared to spray them with anything else right now..

-GC

Larvae don't have wings. All flies undergo complete metamorphosis- I.e. egg, larvae, pupae, adult. It's the larval stage you need to worry about as they are just eating machines. Once they emerge into adulthood their only purpose is to mate and lay eggs.

Try encouraging natural predators into your cactus patch - e.g. ladybirds, spiders, wasps etc.

 

[G_Chem]

Larvae don't have wings. All flies undergo complete metamorphosis- I.e. egg, larvae, pupae, adult. It's the larval stage you need to worry about as they are just eating machines. Once they emerge into adulthood their only purpose is to mate and lay eggs.

Try encouraging natural predators into your cactus patch - e.g. ladybirds, spiders, wasps etc.

Funny you mention, one of them had a tiny bug I almost squashed until I looked closer and saw it was a tiny spider that made a home. I should go outside and bring more in, my wife would love that

I left spidey and hope more come around to eat the rest.

-GC

 

[darvocet21]

get some