brown rot pandemic

[TyroneGenade]

Hello,

I have a serious problem. There is some or other bacteria killing my plants and it moves fast. Sunday my last surviving growth of Paph armeniacum was healthy and Monday morning it had rotted off. Whatever this is, it moves fast.

The problem first occurred in summer/fall of this year when I lost all my Satyriums and several other plants. The leaves just started turning brown and mushy and nothing stopped it. The Paphs seems a bit more resistant but I have now lost several plants to this rot (and it looks like my Gege Hughes is next, all of its attempts to make new growths have failed). I'm also down to my last healthy growth of bessae. Most of my deflasked seedlings are dead and many of my Catts and Onc hybrids have also succumbed. Luckily, my Tolumnia and Restrepia seem resistant.

Anyone have any suggestions? I'm thinking of spraying everything with some dilute hydrogen peroxide to surface sterilize everything.

 

[ehanes7612]

what is your day humidity? and what is it at night?..if you have a rapid change in humidity from day to night (say 60 to 80 or 70 to 90%). this can cause problems over a period of time..especially if you dont have enough airflow..it can also depend on the shape of your greenhouse , some greenhouses create natural dead spaces..i had to put three fans in my 10 x 12 space because of the half A frame, but when i had a half dome (12 x 15) i only needed one fan. also have to consider anything that weakens plants in general ..such as drying out too much or too much light or whatever

 

[dodidoki]

Use natrium hypochlorite solution for watering ( 10 ml/l). It will made miracle!!!
(for prevention and stop infection spreading). Sick plants will plobably die.

 

[Shiva]

I always use hydrogen peroxyde at a 3% solution plus an application of straight sulphur on the affected areas, to prevent fungus from colonizing the sick plant. Works most of the time, but the affected leaves are done for. I have a paph parishii that got attacked two months ago. I only have the newest leaf left and can still hope it will start to grow again.

 

[wjs2nd]

I was thinking hydrogen peroxide too. Good luck Tyrone! I'm sorry to hear about all your plants/orchids!

 

[Justin]

Sounds like erwina.

Do you have access to phyton 27? That will stop the bleeding but then you will have to find the cultural issue that fostered the spread.

 

[TyroneGenade]

My Satyriums were growing out doors in the wind... Now I'm living in a very different environment and the problem is still occurring. This isn't a humidity problem.

3% H2O2 it will be. It will try bleach (sodium hypochlorite) next.

I got luck with my Paph phil. I just cut off the leaf...

Thanks for the advice.

 

[quiltergal]

I agree with Justin. It sounds like Erwinia which is bacterial and spreads like wildfire. Cut off all affected parts back to healthy green tissue, and dust the cuts with cinnamon. Make sure you sterilize tools between plants. I have heard that Erwinia spreads by water splashing from one plant to another.

 

[likespaphs]

i think it may be erwinia too
is the rot stinky?

 

[cnycharles]

is there any chance you've sprayed anything different lately or there is something in your water or the chemistry has changed? just that how you mention that nothing has stopped the rot, it could be something different than what you might be expecting. though spraying fungicide on bacterial infections wouldn't do anything. copper sulfate can help with bacteria as well as the other advice, and watering with a lot of calcium can't hurt

 

[SlipperKing]

Tyrone,
I searched all afternoon and came up with this interesting article on controlling Erwinia. I believe salicylic acid is one of the main components of aspirin.
http://www.ejp.eg.net/vol.35.No2/6.pdf

the meat and potatopoke of the article is high lighted below.
R e s u l t s a n d D i s c u s s i o n
1. Effect of some resistance inducing factors against bacterial soft rot of potato:
Application of salicylic acid and BION as resistance inducing factors has
significantly decreased severity of bacterial soft rot disease of potato compared with
the control (Fig.1 A&B). Percentage of disease reduction was increased by
increasing the rate of salicylic acid and BION. Efficiency of salicylic was more
effective against the disease than BION. Also, salicylic acid was the most effective
to reduce the disease, at 9 mM, where percentage of disease reduction was 100%.
Applications of salicylic acid lead to decrease the disease, when this compound was
applied at the same time or after inoculation with the pathogen. Meanwhile,
application of BION tends to reduce the disease, when it was applied before
inoculation with the pathogen. These results are in agreement with Abd El-Sayed
et al. (2003). The effect of salicylic acid was not caused by direct action on the
growth of pathogen, but the effect of was rather a consequence of induction of plant
defense response (Malamy and Klessing, 1992). Many Biochemical changes occur
during systemic acquired resistance (SAR), i.e. pathogenesis- related (PR) proteins.
Acidic PR-proteins including acidic B-1.3 glucanase and chitinase are secreted in
the intercellular spaces, where they would act against fungal and or bacterial
pathogens at early stage of infection process. Basic B,1,3-glucanase and chitinase
accumulate in the vacuole, may interact with pathogens, at a later stage of infection,
during host cell deterioration (Ye et al., 1995 and Kuc, 1995).
2. Effect of some salt compounds against bacterial soft rot of potato:
Application of potassium sulfate, ammonium phosphate and calcium chloride as
salt compounds significantly decreased severity of bacterial soft rot disease of potato
compared with the control (Fig. 2A&B). Efficiency of salt compounds was
increased against the disease by increasing their rate. Severity of bacterial soft rot of
potato was completely reduced, when potassium sulfate and calcium chloride
were applied at 0.5 g/l and at the same time of inoculation with the pathogen. Tested

 

[cnycharles]

there you go; dust and powder all of your plants with calcium chloride
(deep freeze rock salt) and then salicylic acid

 

[Paph_LdyMacBeth]

Wow Tyrone I'm sorry your going through this. I had a battle with erwinia in my phrags last summer...I ended up just tossing the affected plants after tying to treat them multiple times. It was hard, but the right thing to do for me.
Others have had great suggestions. I wish you success!

 

[abax]

Will Cleary's 3336 have an effect on erwinia? I've never had the problem
and wonder if occasional use of Cleary's might have been of some help.

 

[quiltergal]

Cleary's is a systemic fungicide. It won't cure a bacterial outbreak.

 

[TyroneGenade]

Thanks for all the advice and insights. CaCl2 and asprin to the rescue!

 

[Ozpaph]

Better use dissolvable aspirin.

 

[eggshells]

Increase calcium and magnesium supplement once you are done treating them. Helps to supress erwinia.

Similar paper of what Rick linked regarding erwinia.

http://www.nzpps.org/journal/50/nzpp_505350.pdf

 

[Rick]

The problems of erwinia associated with plants (especially perennial species) was part of the logic for low K feeding.

One of the papers I found on the supplementation of Ca to potatoes showed that resistance to erwinia was low when leaf tissue concentrations of K exceeded Ca. Subsequently increasing Ca to offset K was instrumental in increasing resistance to erwinia in potatoes ( a domesticated annual species).

In tropical epiphytes we have documentation that K is selectively absorbed to the detriment of Ca uptake. Subsequently, in order to avoid high K levels in orchids, K supplementation from fertilizer needs to be restricted and offset by high Ca concentrations.

Tyrone, I don't know what your present fertilizer system is, but many of us have noted greatly reduced (if not completely eliminated) problems with erwinia since going to a low K/high Ca,Mg feeding regime.

As noted from above the use of K sulfate and Ca chloride for potatoes, but note that potatoes are a high K use plant, and the sulfur (sulfate) is a critical component of the addition. You might see if you can use calcium sulfate (Gypsum) instead of the chloride form of Ca. It's not as soluble, but could also be used as a top dress.

 

[Rick]

I think this math has been done before for the asprin addition, but:

the molar mass of salysilic acid is 138 g/mol

so 9mM solution is 1.25 g/L which is 4.7 g/gallon