Sudden leaf issues
 

Hello all,

I gifted my friend with a partition of my cymbidium 2 years ago, and it has been doing very well, new growth, blooming.

Today he messaged me, that between waterings the damage you see in the pictures happened (50% of the leaves are affected)... He is ocd about plants (the reason I gave him the partition), so I am sure this damage was not there at the last watering. The only things out of the ordinary were:
- watering was done in 10 days not 7 as usual
- fertilised as normal (1x month)
- we went into abrupt autumn (the plant is inside tho)

I hope this has a solution, as I have never experienced this, and am at whit's end :-(

Thank you for any info,
Jakub

I wonder about spider mite damage if the air is warm with low humidity. Run a piece of tissue paper under the leaf from base to tip. If there are brown or red streaks there are spider mites.

Or, if very fine silvery cobwebbing can be seen under the leaves, there are spider mites.

Spider mites are almost microscopic 8-legged arthropods. Most people cannot see them.

The wile came away with some stains as in the picture (toilet paper + the leaf it was taken from), also my friend noticed some small bugs on the pot (also on picture).

Spider mites are outside in the landscape, so you cannot get rid of them permanently. I don't use poisons in areas where I will spend time.

They can be controlled by spraying the entire plant with a solution of 3-5ml liquid dish soap per liter of water. All leaf surfaces must be wet. The solution must get into the crevices at the bases of the leaves. The soil surface must also be wet with the soap mixture.

The mites are almost certainly on almost all the other plants in the area. They should be treated, too.

This will not kill all the eggs so it must be repeated every 3-5 days for 3-4 treatments. Afterward it is enough to spray all surfaces with the dish soap solution once a month. Plain water will also control them because it kills the eggs, but the dish soap works faster.

70% alcohol also works. It is more expensive.

Spider mites are not very active when the relative humidity is 80% or over. They prefer warm temperatures and low relative humidity.

I do think you have your answer... spider mites. And some very good advice for controlling them.

I would question the watering regimen ... Cyms like to stay somewhat damp. (Mine are outside, get a lot of heat and bright light, and get watered every other day) Fertilizing is probably not adequate, but that would not cause the damage, only the plants will grow more slowly. (Ideal leaf color is light green, even a little bit of yellow-green. Dark green indicates inadequate light which will reduce blooming) I use time-release fertilizer pellets in addition to my regular (light) feeding of all of my orchids. Since I started doing that, growth and blooming were better. But the sudden damage, those nasty spider mites! Attack them!

Thank you both!

All points were noted, and are now being implemented :-)

I will let you know the update in a couple of weeks.

Jakub

An update - after treatment the damage has stopped, and the plant is looking much better.

Keep on it. One treatment isn't enough.

Yup! My friend is keeping the regiment as written here.

My plants are in an area where I can spray everything with a hose. I do this every 2-3 weeks to prevent spider mites outbreaks. If I couldn't do that I would take each plant to the shower and spray it instead. Plain water is enough to control them if done regularly.