What is happening to my orchids' leaves (2 plants)???

[wintergirl]

Originally Posted by majormtn

Will alcohol hurt the leaves?

No it will not hurt the leaves. It will kill and wipe off the mites if you have them.

Here is a recent thread on spider mites:

Treating Spider Mites

[djf051]

Originally Posted by majormtn

...Djf051, would these bugs be on the leaves too? Would you suggest I spray the leaves with hydrogen peroxide

The three kinds of mites that usually infest orchids are very small and they don't move that fast either, so you really can't see them without a 10X field lens. With magnification you can see the damage better, you'll possibly see live mites, but you'll also likely to see dead mites, or their shed skins, or eggs or web. Phalaenopsis mites though don't produce web.

If you don't have mites, the junk on the leaves will be just that, random flecks of detritus, all different sizes and shapes.

I don't know what effect hydrogen peroxide might have on mites. When I have had problems, I used insecticidal soap. I also wash the plants often. Mites thrive when the air is very dry, so I use a humidifier in the winter.

[orchids44]

your first picture definitely looks indicative of phalaenopsis mites. They're not visible to the naked eye and don't spin webs. Bayer 3 in 1 works, 3 applications, 7-10 days between each application. The underside leaf normally has more damage. Isolate the plant, they spread and are common this time of year. Our dry heat and lack of air circulation helps them multiple. Good luck.

[majormtn]

Thanks for the great advice everyone! I will repost photos if I see improvement

[MrHappyRotter]

I think the damage is indicative of mites as well.

Sometimes mite infestations are also a symptom of other issues, weakened plants are susceptible to bacteria, fungus, and critters. It could be that the roots are in bad shape, and thus the plant's health is compromised. Mites could also be a sign that the humidity is low.

Either way, there are multiple options for treatment. Alcohol is an option. But you have to be persistent with it, and you need to follow up several times a week, for as long as it takes.

The best option I've found is to treat with a combination of contact and systemic pesticides, every 10 - 14 days as directed, alternating treatments for a month or two.

Then you can use a preventative option once a month. This would include Neem oil, cinnamon extract, horticultural oils, insecticidal soap, or contact sprays.