# Markings on Coelogyne leaves.



## Tom499 (Sep 17, 2012)

I'm not sure if these are multiple problems. I noticed older leaves dying off, which I was thought was fine.

But now I'm seeing newer leaves with these markings. Its more prominent on the underside. I'm wondering if it could be sunburn.

It is the white and reddy powder like tiny spots that worry me. I don't have magnification to determine whether they are an insect, they do brush up easily though.


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## NYEric (Sep 17, 2012)

rub w/ alcohol! could be mites..


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## Tom499 (Sep 17, 2012)

Mites are definitely my fear.

Would white spirit work? 100% or diluted?


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## Cochlopetalum (Sep 17, 2012)

False spidermites, they love Coelogyne.


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## NYEric (Sep 17, 2012)

Seems kind of harsh. maybe someone else knows.


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## SlipperFan (Sep 17, 2012)

Looks like a spider mite infestation to me. I used SucraShield sold by Ray Barkalow to treat an infestation I had on my Paphs and Phals a few years ago. It worked well.


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## Rick (Sep 17, 2012)

I never knew there was enough sunshine in the UK to sunburn a plantoke:oke:

I haven't messed with Coelogynes in a long time, but they have fairly thin leaves and are prone to low humidity dessication. Spider mites are frequently another symptom of a low humidity environment.

This could also be another case of salt/fertilizer imbalance causing water regulation/nutrient problems (shedding of lower leaves).

Healthy plants are often pest resistant to start with, rather than external pests causing otherwise healthy plants to stress and crash.

I'd start reviewing your general culture before getting too excited about pest control.


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## Tom499 (Sep 18, 2012)

I'm guessing too much sun may have weakened some of the leaves.

Two of the plants made 8 new growths, and all have matured nicely.

The third one however has been weak for awhile, and looks to be the main source of the problem. I may just throw it out.


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## Ozpaph (Sep 18, 2012)

classic mite infection.


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## Tom499 (Sep 18, 2012)

I've started the clean up. 1st I'm going to change their positions to a cold frame greenhouse, where the humidity will be higher and less sunny. 

I'm wiping down the leaves, at the moment with just water, to clean them up. I've found various cures for mites, from wiping the leaves with soap to alcohol.

I was looking to purchase an insecticidal soap, and avoid the use of broad spectrum insecticides. 

Would a regular old fashioned hand soap with water be just as good? With a leaf rinse afterwards.


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## goldenrose (Sep 18, 2012)

Tom499 said:


> ....I'm wiping down the leaves, at the moment with just water, to clean them up. I've found various cures for mites, from wiping the leaves with soap to alcohol.
> 
> I was looking to purchase an insecticidal soap, and avoid the use of broad spectrum insecticides.
> 
> Would a regular old fashioned hand soap with water be just as good? With a leaf rinse afterwards.


IME mites are a bear to 'cure'. 
I'm with you on the use of insecticides.
Not sure what regular old fashioned hand soap. I'd go with the liquid peppermint soap found at health food stores. Supposedly this is all Glenn Decker uses, 4T./qt water.


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## Tom499 (Sep 18, 2012)

I mean the regular bar of soap of old. I've heard you make a soap solution, rub it on, then rinse with water 30mins later.

I'll look out for peppermint soap tomorrow.

I think this will be cured by a change in climate for them, but I definitely need to hurt the mites as they seem pretty established.


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## Tom499 (Sep 24, 2012)

Bit of an update.

I have decided to no use anything other than water on the leaves. I'm soaking and rubbing them with water daily.

The three Coelogyne are now at home in a cold frame greenhouse, where temperatures will be 5-10 celsius night/day, due to the wet, depressing weather we're having. 

I have cut off the worst affected leaves in the hope I will be discarding mites and eggs along with them. 

While I do now run the risk of fungal attack, I am hoping to drive off the mites with cold, wet conditions over the next few weeks, and then start to water the Coelogyne less into winter. 

The plants are:

Coelogyne Unchained Melody (cristata x flaccida)
Coelogyne Intermedia (cristata x tomentosa)
Coelogyne tomentosa

So they should be fine, as they would be getting similiar conditions (though dryer) towards this time of year anyway.


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## Roth (Sep 24, 2012)

Brevipalpus mites. Use dicofol, it should be efficient, and I think it is still available in the UK Garden Centers. 

Brevipalpus is absolutely not sensitive to humidity/drought or wet/cold at all...


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## Tom499 (Sep 24, 2012)

I can't get hold of that. It sounds like a very harsh chemical.

The only false spider mite isecticide available to me was Bifenthrin, which I think is still found in a few insecticides.

but:

"The Commission of the European Union has published the date of 30 May 2010 when the approval of all pesticides containing bifenthrin will cease and sales to the UK public must stop. The public will have a further 12 months after sales cease in which to store and use up any remaining products that contain bifenthrin."

I have a bottle of Rose Clear which contains bifenthrin, but legally I shouldn't be using it. 

If I can't get rid of the mites through changes in environmental conditions, I'll try the soap route. From what I can gather, I just need a 1-2% soap solution, but can add a little vegetable oil to help it "stick" to the leaves and mites.

For the soap, I figure I can use a small chunk from a bar of regular hand soap, and melt it in hot water? 

http://en.wikipedia.org/wiki/Soap


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## biothanasis (Sep 25, 2012)

Hi, for mites I have occasionally used a soap solution quite successfully, which should be used cautiously so that one is sure not to damage the leaves and him/her - self.

Add 1-2 Tblspoon of dishwashing soap (the simplest available - avoid having added aromatic materials), 1-2 Tblspoon of tabasco, 1 teaspoon of rubing alcohol in a litre of water. Stir mildly so that the mixture does not produce (a lot of) foam. You can put a bit of vegetable oil (1 teaspoon) so that the solution stays on the leaves longer.

Although is does not contain chemicals, it could still be disturbing for your respiratoral system or your eyes, so be carefull when spraying. Additionally, spray on one spot, e.g. tip of lower leaf of the infected plant to firstly check if the leaf gets damaged or not, so that you might have to diluted the solution a bit more . Depending on the life-ciycle of the mites you will have to repeat the spraying at an adequate rate. Additionally, insist on the underside of leaves, as this is where they reside mostly. If you put oil in the mixture, remember that it will take about 3-4 days for the odor of the solution to stop. 

Good luck!


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