Bad winter: Bacterial Issue?

[Lars Kurth]

This is the second item in the "Bad winter issue series". I am hoping that maybe somebody can help me identify what it is.

I have had a terrible winter in my greenhouse. I was not around much (travelling 3 weeks out of the month for work) for nearly 5 months now and having other people looking after the greenhouse. I often only had a day in between trips and just enough time to wash clothes.

As a consequence I now have a mixture of diseases as well as maybe cultural issues.

This disease seems to ONLY affect soft tissued and leafed plants, such as Gongora & friends, new growth of Stanhopea, new growth of Dendrochilum, new growth of soft Coelogyne (e.g. Coelogyne payishii), Ornithocephalus. It is VERY fast.

The disease always starts from the tip of leaves on new shoots, which become yellow on the leaf tip. The yellow moves rapidly down the vains, and the tissue dries behind. Sometimes you can see a slight blue sheen on the dried tissue. When the yellow has wandered to the pseudobulb, it becomes yellow, then brown and mushy. When you prick the skin liquid goo comes out. It does not smell. The speed of the disease implies something bacterial. Cutting off the affected leaves before a pseudobulb is affected seems to save the plant (or at least slow the disease), but it can come back. Sometimes watery blisters on leaves.

This has been the biggest issue for me while I was away, as it moves so fast. I had no indication of any issues when I left for a 2 week trip in January: when I got back, many plants were mush.

See attached pictures of early stages, which I have taken over time.

[quiltergal]

That looks like erwinia to me. Spreads like wildfire! Cut off all affected parts and disinfect tools well. I have seen this wipe out entire collections.

[The Mutant]

Could it be Anthracnose? I'm a complete newbie so don't take my suggestion too seriously. I've compared images on this really good site (St. Augustine Orchid Society, I actually think it's you who linked to it in the first place) with those of your plants and this is the one that seems to correspond the best with the disease starting at the tip and moving towards the base of the leaf.

Here's a link: Orchid Diseases

[fishmommy]

If it is erwinia I had good results from

1) immediately cut off all affected tissue
2) clean/disinfect entire growing area including all pots and potting media with Phyton 27
3) spray all plants with Phyton 27 according to package instructions, but sacrifice buds/blooms in favor of spraying.
4) Throw out any standing water and disinfect with Phyton 27. Discontinue any splashing or water sharing activities permanently - this disease travels with the water.
5) Let the growing area dry out a bit and remain a bit dryer than I had been keeping it if possible.
6)Toss out any persistently infected plants
7) Wait and watch

I only lost 2 plants when I got it, and considered myself lucky. It moves so quickly.

[Lars Kurth]

That looks like erwinia to me. Spreads like wildfire! Cut off all affected parts and disinfect tools well. I have seen this wipe out entire collections.

That is what I have been thinking too, but there are not many pictures on Erwinia on plants other than Paphs and Phals. So I have been spraying with Phyton 27, which seems to help control it. I have also sprayed with Cleary's. I am going away again for 3 weeks: so fingers crossed that the fungicide regime that I have been running in the last 2 weeks, will help the greenhouse get through the 3 weeks that I am away.

I also have been disinfecting water supply, and greenhouse floor with Physan and H2O2 and have been throwing out plants that were more heavily affected immediately.

The plan is to spray two days before I leave with Phyton 27 and spray the plants that tolerate it with a copper based fungicide afterwards. The day after coat the plants with Agrobest ENVY. That should allow to get the greenhouse get by with less water and should help with control. Let's hope it is enough.

[BikerDoc5968]

Lars, I would have to say Erwinia, also, as this devastated my Phals this past summer; I must have lost 30 to 40 plants to crown rot or just DEAD! As has been said previously it can rapidly destroy a plant. I tried Phyton 27 with NO effect! I sprayed Physan-20 mixed 1 1/2 times stronger than directed and sprayed EVERYWHERE! This slowed things down but you have to do it frequently. Removing affected parts is paramount. Using cinnamon seemed to work well. If you can find agricultural Streptmycin, this is the gold standard. Erwinia, not to get too scientific, is a gram negative bacteria and the Steptomycin is very effective in killing this type of organism. Also, Cipro which is readily available and cheap should work also, since it is very active against gram negative bacteria. Cipro is very soluble in water, especially if the water is warmed to about 120F (50C), then spray it everywhere. You may have to repeat the Physan or Cipro routine. Sorry to hear about your situation. I know also you have adequate air circulation because moisture promotes the growth of the bacteria. And like other types of infections, general spraying with water spreads the nasty stuff.

[fishmommy]

oh that's so scary that Phyton 27 didn't work!

I also found that making more space between plants in the growing area to help stop the spread. Splashing spreads it so keeping a dry zone around each plant is a good long-term strategy I am following.

[Lars Kurth]

If you can find agricultural Streptmycin, this is the gold standard.

There seems to be a product called Agri-Mycin® 17, but I can't get it.

[Leafmite]

Winter IS a bad time for plants. I've had my fun already with black rot and a few of my cattleyas. Good luck, hope you reign victorious!

[fishmommy]

yes good luck!