Brown reddish dots on Brassola Nodosa - Orchid Board

babehauss · #1 03-09-2021, 11:53 AM

Hi Everyone,
Could someone help me please ?

My Brassola Nodosa developed these brown reddish dots on the leaves. Is this a fungal/light problem?

This plant had a scale problem at one time and I control it by brushing the leaves with a very soft toothbrush dipping in 70% isopropyl alcohol.

I grow my orchids under light.
Light: SpiderFarm SF 1000 setting at maximum light intensity (450 ppfd).
Humidity: approx 40%.
Thanks

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Roberta · #2 03-09-2021, 12:02 PM

This could be the result of damage that the scale did before you got rid of it - the damage was stopped but the marks won't go away. I wouldn't worry about it. Any chance that it might have gotten cold? That can do it too. I doubt that light is the problem, these can take rather high light.

Orchidtinkerer · #3 03-09-2021, 12:44 PM

This is a nutritional issue - most likely from using Tap water.

You are either feeding too much calcium from tap water or your ph is off. This in turn is locking out magnesium and potassium.

Roberta · #4 03-09-2021, 01:03 PM

Before diagnosing a nutritional issue, it would be useful to know something about the composition of the tap water, as well as pH ... a lot of people have have tap water with pH around 8 and the orchids do fine. Also, if there were an issue due to water, I'd expect to see it in other plants as well. B. nodosa is quite forgiving of water and fertilizer issues, as are most of the rest of the Cattleya tribe.

Orchidtinkerer · #5 03-09-2021, 01:45 PM

just trying to help as I know the problem but I also know nutritional issues are considered the last culprit so lets rule out the others first.

It isn't sunburn
It aint pests.
Doesn't look dehydrated so not a watering issue.
Doesn't look like cold damage.

Then again I have technically retired but can't seem to stop helping but everytime I get questioned like I don't know what I'm talking about, whatever.

Have a nice day peeps. I should be watering my plants anyway..

Leafmite · #6 03-09-2021, 09:34 PM

I have had my Brassavola nodosa and other Cattleyas get reddish coloration during the summer when they get high light and it doesn't seem to hurt them. I always thought it was from higher light but I know with other plants that reddish leaves can signal a nutritional deficiency (often cooler temperatures combined with the deficiency will cause the leaves to turn red). The reddish color, for me, always fades shortly after bringing in the plants.