Hello everybody,my name is Marianna,I'm from Italy and I'm growing Paphs (michrantum,armeniacum,philippinense,emersonii,del enatii,nivaeum,villosum var. annamense album,lowii,gratrixianum,primulinum x delenatii,moquettianum x delenatii) since three years.Some are grown in a large orchidarium,under a 150 W HQI light.The cool-growing ones are on a windowsill.
Yesterday I noticed a light-brown elongated spot on the younger leaf of my primulinum x delenatii,and I treated the whole plant with a fungicide (mancozeb,penconazole and copper),but today I've found a brand-new spot and some little spottings around the bigger-two ones...so I think the disease is spreading very fastly and I'm very concerned, for mancozeb seems not to stop it.
Here's a pic of it:
http://i48.tinypic.com/14jnmzs.jpg
Average temperatures in this season are: day 23 C- night 16 C, U.R. 65%.
I water with r.o. and fertilize weakly weekly.The plant is kept rather on the dry side and looks (ehm...looked) healthy.
Could it be bacterial?
Have you seen anything similar?
Thanks for your kind attenction.

Welcome to a wonderful forum! Your plant looks like it has some mechanical damage or even sunburn.

Welcome to a wonderful forum! Your plant looks like it has some mechanical damage or even sunburn.

:iagree: It doesn't look like pests. The only other bug that is brown is scale, and that definitely is not scale.

:hi::welcomesof:

Thanks for your replies (and for your welcome!!!):D
I'll keep you updated...I can't remember any sort of mechanical "accident",and the plant is kept into my orchidarium,where the only source of light is artificial...but if you say so,I'm a bit more relieved.

Welcome! It doesnt look like pests to me but do keep an eye on it.

Welcome! I'm also a new forum member.

Thanks casey and phragmip!
casey:the plant is still kept in isolation...:fcrossed:

Hi Marianna welcome to the slipper orchid forum and it is a great pleasure to have you here! I also agree with the other members that it doesn't look like it was caused by insects. Keep your fingers crossed and hope that it doesn't spread!:fcrossed:

Welcome to the forum.

I also think it is not pest related. Welcome to the Slipper Orchid Forum and thanks for joining!

orchidlover,skipper,paphraguy:thank you very much!
Tomorrow I'm going to remove some of the cinnamon dust and see what's happening on the leaf's surface...
By the way: can you tell me if P. deperle needs 15 C° at night to be brought to bloom as it does his parent P. delenatii? Mine hasn't re-bloomed yet after two years of cultivation into the orchid case...maybe night temperatures too high (18 C°)? Sorry for the O.T. :embarass::embarass:

Plants will only flower on growths that are mature. I think your plant growth is not ready to bloom yet.

Hi Marianna...:welcomesof:

Hi Casey,thanks.So it's only a matter of patience...
Hi Slipperguy,thanks!
Today I removed some cinnamon dust from the leaf and it seems that spots didn't enlarge their size.:Party:

That is wonderful and do keep us updated! You did great!