Insects are destroying my collection

[obsidian]

I just got home from college and I fear that my entire collection is in jeopardy. About half of my in-ground trichs are rotten and I am seeking advice on how to protect the rest.

 

Here's what I think happened. I put around 10 semi-monstrose bridgesii in the ground several years ago that couldn't handle the 9B winters. They were susceptible to black rot induced by frost and I was going to move them back into pots to keep them protected during the winter. I've dealt with black rot on other varieties of in-ground bridgesii and it was never a big deal, just cosmetic damage that scabbed over, but the semi-monstrose ones had more difficulty recovering. So I planted these semi-monstrose all next to each other spaced a meter apart and I believe they were the first ones to become infested. My neighbor grows wheat adjacent to the cacti and made bales about a month ago. The bales are currently infested with millions of these tiny insects that have an appetite for my trichs. I think that the insects living in the bales found some rot on the semi-monstrose bridgesii and became the vector that spread the rot to the healthy cacti. There appears to be a chronosequence of the spread of the rot, as the cacti farther away from the semi-monstrose are less infested while the cacti closer are more infested. My neighbor is coming over with a tractor and all of the rotten ones are getting buried asap and the bales are going to be moved away from the cacti. 

 

This disease spread very rapidly. About a month ago I had a friend send me pictures of the plants and they were all thriving. Even some of the most hardy plants in my collection are now completely covered in the rot and crawling with these insects. I am hesitant to spray my plants but I will do whatever is necessary to protect the healthy ones. Does anyone have a recommendation for an insecticide? Has anyone dealt with this before? Any advice will be greatly appreciated.

[Evil Genius]

Pretty sure this is a secondary infection caused by cold damage. If you want to get to the root of this you need to protect them from frost or it will happen again. Those instects can be killed with Neem and it shouldnt be a big problem to get rid of the insects. The real problem is the rot that you have there. I would use sulfur, neem and maybe 60-70% alcohol to get this plant back on track.

[theuserformallyknownasd00d]

Oh man so sorry for your plants! I'd follow EGs guide to the T, I dunno what else can be suggested!

 

thanks a lot for the detailed post too, I am about to plant a heap of trichs in zone 9-9b and will definatly rethink my strategies now. Possibly even not do it!

 

goodluck with it mate 

[obsidian]

Thanks for the fast reply Evil Genius. Some of the affected plants in this area have been in the ground for 8 years and they have never had a serious issue with frost damage. It has been several months since the last frost and other unprotected cacti on parts of the property show no frost damage from the last winter. The rot seems to be linked with the presence of infested bales. Earlier this morning, the plants were covered with insects but they have retreated to the weeds at the bases of the plants to escape the heat. I am currently clearing the dead grass and weeds from the cacti so they dont have a place to take shelter. I will spray the neem solution tonight.

[Evil Genius]

Yes but be super careful and if you can get a non-oily Neem solution it would be the better option. Neem oil can cause chemical burns, especially when sprayed in summer. If you dont get the Neem chemical as a toxin make sure to dilute the oil mix. And get yourself some sulfur because it is a great way to get sick plants back on track. No matter what; this will take years to heal.

[sagiXsagi]

It almost looks like the bugs like the rotting cactus. Could they like and thus worsen the bacterial black rot expression?

 

I have had snow damage in severar trichos and it never looked all-black.. but sure, EG knows better from cold

 

Sorry for your damage

[zelly]

two questions mate,

 

 

1) zone b- what are the lowest winter temps you typically experience

2) can you be more specific in your location?

 

imho theres a lot more at play here than freezing temps, black rot & bugs 
 

[MoonUnitBotanica]

Invest in a cactus house. Wrong climate buddie for outdoor growing.

[Evil Genius]

It is the textbook case of winter damage. I agree you might want to think about winter protection. It´s not normal that plants get something like that unless there is something wrong with the environment. Like previously mentioned; get yourself a cheap greenhouse. You dont need to spend much to prevent something like this in the future. It´s an amazing plant and it will rise again. :-D

[obsidian]

Hey everyone. I felt it was necessary to remove most of the sick plants to protect the healthy ones. I might have gone a bit overboard but I have replacements for the ones that were removed. I discussed the problem with my neighbor who grew the wheat and he said they were whiteflies but I'm not sure he really knows what they are. The cacti are not far from Vista, Ca so I'm not convinced that climate is the main culprit. They get a few cold nights that reach the high 20's, but the majority of the cacti just get minor damage or show no significant damage, especially when they are not overwatered. I fortunately have a protected cactus area where I grow out cuttings and a few seedlings. I definitely neglected the garden but I was going to school far away and only got the opportunity to work on the plants for a few weeks during summer. The crazy thing is how fast the disease spread, they looked completely healthy in the pictures I had received a month ago while I was away from them. I will now be sure to throw some burlap bags or something on them during the coldest nights.

 

The cacti that were affected had been planted in a row along a fence. I just took two pictures of bridgesii from the same row that are unaffected. The other picture shows the burial of the more severely damaged plants. I didn't get around to spraying them yet but plan on doing that tonight. Thanks for the kind words and advice!

[2XB]

I'm not sure why you guys are certain its cold damage..  From the info given by  obsidian it doesn't seem likely, ie they're in the same spot for 8 years with no problem and months since a frost...

Plenty of trichocereus growers successfully grow with zone 9b winters... Both Dawson's and Field's gardens here in australia would be considered 9b winters?????

Surely there is something else happening here..???

 

Edited June 5, 2016 by doublebenno

[waterboy 2.0]

chem drift from the adjacent field ??

[MoonUnitBotanica]

^ great point. One of my bro in laws thought he was doing me a favour by spraying glysophate around the border of my cactus garden. The cacti that copped the spray got some weeping black sores where the spray had got them.

[MoonUnitBotanica]

They did recover with a little scarring.

[zelly]

On Friday, June 03, 2016 at 9:46 AM, zelly said:

two questions mate,

 

 

 

 

1) zone b- what are the lowest winter temps you typically experience

2) can you be more specific in your location?

 

 

imho theres a lot more at play here than freezing temps, black rot & bugs 

 

 

Like I said, theres a lot more in play here than freezing temps.

 

My plants have experienced lows of 27F-28F and the only thing that has ever froze was a 3 meter Pilocereus azureus last winter; no damage whatsoever on any trich.

 

Looks more & more like your wheat farmer neighbor spraying for bugs got some over spray on your plants.  IMHO your third, fourth & fifth pics down from above are not indicative of 'cold weather damage', regardless of who thinks they are.  The fifth pic is really telling.  No way in hell is that 'cold weather damage'.

 

[sagiXsagi]

yep. a chemical burn or something, or multiple problems at once? 

 

I haven't seen trichocerei, even bridgesii which are more black rot prone and less cold hardy, to get so extensive damage from whatever cause..  

 

how cold can it get in california? its supposed to be more or less the same climate with central and southern greece.. we even get the same species of mushrooms  .

 

 

[zelly]

3 hours ago, sagiXsagi said:

how cold can it get in california?

Cali is a mighty big & diverse state with temperature swings from 134F to -45F

http://www.infoplease.com/ipa/A0930157.html

 

 

Record highs & lows in my area are 110F to 22F

 

i'm of the opinion that plants grown in the ground for numerous years have somewhat 'climatized' themselves for that particular area and are able to survive extremes that would otherwise damage or kill them.

 

 

Another factor is humidity in conjunction with freezing temps.  A heavy fog with below freezing temps was lethal to several tropicals (Pv in particular) that  otherwise did just fine with freezing temps and much less relative humidity.