spreading disease

[geraldw3210]

h all i have something spreading through my plants. black spots , yellowing bottom leaves which drop off at the stem. this might be from the rainwater im using on them its been stored for a couple of months.

il need too get some distilled water too use.
plus my plants are indoors now it get kinda cool here at night and of course lighting is dimmer not full sun lie spring summer.

so clean water and do i need too treat the plants with anything? i have thiomyl, physan 20,and liquid copper. any of these work?

[Orchid Whisperer]

I have used captured rain water that has been stored for a year more with no problems (I do run it through a plastic coffee filter/paper towel filter before I store it in plastic, & I keep a lid on to keep out debris). I don't think the rainwater is the issue.

Not seeing that leaf in context, but yellowed bottom leaves could be quite normal. The circular spots could be bacterial or fungal. Sometimes you see this type of spotting if the plants are kept too cold and/or too wet. What are your growing conditions like? Are you supplying calcium? If you have the growing conditions right and are still having problems, then it may be time to get out the chemicals.

[Leafmite]

I had to buy a Calcium/magnesium supplement for my orchids not long ago as I was having some yellowing leaves. I might need to add a little Ironite to the mix, too. I am using distilled water for my goldfish tub and apparently, the goldfish are not a complete alternative fertilizer source.
Though, perhaps it is also those cooler night temperatures causing the issues....
Calcium does help prevent issues but it takes a while to see results as it only strengthens the cells that are being built (new growth). If you are seeing much of this, you will need to use a systemic to clear up the issue quickly and then you should find a way to add Calcium to your orchids.
Good luck!

[wintergirl]

I use unfiltered rain water stored in plastic jugs for months without problems, so I don't think that is the problem either.

[Orchid Whisperer]

Sometimes supplying that needed calcium can be really simple. Read the introduction to following, which describes how stored rain water acquired adequate calcium for orchids merely by being stored in a concrete cistern: http://staugorchidsociety.org/PDF/20...ps-Calcium.pdf
(The rest of it is a good read too)

[fishmom]

Interesting link--thanks for posting it!

[geraldw3210]

Originally Posted by wintergirl

I use unfiltered rain water stored in plastic jugs for months without problems, so I don't think that is the problem either.

Thank you one less issue

[Selmo]

Looks like erwinia (brown rot). If that is a phal leaf in photo. You had better act fast, if it gets to the crown it can be fatal. Spray it with Physan,it should stop it from moving any farther. Erwinia can be caused the leaves being wet for long periods of time (4 hours or more) or by using cold water when watering (use room temperature water). Moves from plant to plant by splashing water, so avoid overhead watering( soak pot in container of water). This is only a guess from the photo. Need more info and more photos to make better diagnosis.

[Orchid Whisperer]

Well, the leaf in the photo is separated from the plant & isn't in danger of spreading anything. If the rest of the plant had an active Erwinia infection, cutting off the infected part would be far more effective at stopping the infection than spraying with Physan.

I do think it would be useful to see photos of the living plants. Is it only the yellow leaves that have the circular lesions?

[Selmo]

Dealing with erwinia and other bacterial and fungal rots is what you don't see is what gets you. By the time you see the symptom (the black spots)it is to late. And in phalaenopsis these rots can move though the plant tissue very fast and you can loose your plant in a day or two. So cutting off the black spots or removing the leaf is not good enough. The pathogen has already moved much farther than one might expect, killing the plant. Saying that, I hope that this is not the case with your plant. But something is wrong with it , if the leaves are turning yellow ,and not from the plant just dropping the lower leaves to save energy. With the leaves turning yellow and with the black or gray spot something is going on. The yellowing of the leaf can be caused by a couple of things like to much water, too cold, or even too much sun. These can strees the plant leaving it venerable to diseases. Good luck and I hope this helps