crown rot on Phragmipedium kovachii? Spot on gongora leaf.

[seven5]

Hi is this crown root ?



My Gongora has large black spots on leaves, what is this ?




Please help.

[Eyebabe]

The crown rot on the phrag is most likely pseudomonas and is easily fixed by removing the new growth in total. Phrags are very resilient. Treat the plant with a copper fungicide (which is effective on pseudomonas) and it will put out new hopefully healthier growth down the road. Take care to avoid getting water in the crowns of the new growth etc.

The Gongora leaf looks also like pseudomonas but could also be fungal (looks also a bit like anthracnose). Remove the diseased leaves as much as you can without harming the plant and also treat with a copper fungicide (which is effective for both of these things). Although I can also say some of the spots look a bit like sunburn, a few of them have a yellowish margin that looks soft etc. like an infection. Therefore, I would use the copper fungicide

[seven5]

I sprayed all Gongora with cooper fungicide, all the leaves turning yellow and fell off, new growth turning brown. Apparently they do not like spray with cooper fungicide. Other sprayed orchids is ok.

[Ray]

I have heard from others that such thin-leaved plants as gongoras, coelogynes and the like do not tolerate copper very well. As I have a mixed collection, I avoid it altogether.

[madphrag]

Originally Posted by Ray

I have heard from others that such thin-leaved plants as gongoras, coelogynes and the like do not tolerate copper very well. As I have a mixed collection, I avoid it altogether.

I have the same exact problem with my Gongora and also my Coryanthes. I've tried Physan 20 but it does next to nothing. What would you suggest?

[stefpix]

I got some similar spots on my Gongora. the tip of the leaves. I believe those are sunburn. It happened when I put it outside and it is pretty breezy. I would just have cut off surgically what looked like possibly fungal.

[keithrs]

Unfortunately, your going to have to remove the dieased parts of the plants..... Physan 20 will only work as a preventer. Make sure your tools are soak(unpotted) in a disinfectant before you make the cut and spray or soak the whole plant after with a fungicide, Rainy conditions will only make your problems worst. So, try in cover them and I would repot if you can. When I had my rot problem, I repoted most, used phyton 27 first time I spayed, than physan 20 after in low doses every week for a month with a sticker agent. Can't say this is the right way, but worked for me! The key is to keep the plants dry while they harden off. Good luck with the fight!!!!

[Anisa]

Originally Posted by keithrs

When I had my rot problem, I repoted most, used phyton 27 first time I spayed, than physan 20 after in low doses every week for a month with a sticker agent. Can't say this is the right way, but worked for me! The key is to keep the plants dry while they harden off. Good luck with the fight!!!!

Phyton 27 is cooper based which will likely harm Gongora and other thin leaf orchids. What orchids did you spray with it?

[dounoharm]

i use phyton 27 on my entire collection with no problems...i just am very careful about the proper dosage....you must be exact with this strong chemical....i also use it to wash down the benches....gl

[Ray]

Originally Posted by madphrag

I have the same exact problem with my Gongora and also my Coryanthes. I've tried Physan 20 but it does next to nothing. What would you suggest?

I have gotten really "turned on" by Zero-tol lately.

Bought it as an alternative to Physan for algae control in the greenhouse. The first time I sprayed it - they have these nice "ready to spray" bottles that simply attach to a hose end - the algae on the glazing all but disappeared in a matter of minutes. The plants sustained absolutely no damage whatsoever.

The only negative (not much of one in my book) is the vinegar smell that lasts a few days - the product is a concentrated hydrogen peroxide stabilized with peroxyacetic acid.