Its hard to tell whether this is normal leaf drop, or if you have spider mites or something else. The flush of late summer new growth sounds good. Can you post a ditigal photo? I noticed my sinensis began blooming this week, do you have any blooms or bloom buds?

I have a tea plant camellia sinensis assamica, about a year old. It has developed a reddish brown leaf spot on mature leaves. The brown comes in from the edge of the leaves and spreads over half or more of the leaves. The brown parts become dry and brittle and the leaf soon drops.
I have been watering the leaves with rainwater thinking they were too dry, but I read that this is the worst thing you can do as the fungus causing the disease spreads quickly on wet leaves and can be carried by rain or butt water.
I have now removed diseased leaves and sprayed the plant thoroughly with a systemic fungicide containing carbendazim. I will report on the result!

Good luck and let us know, chrisgg. Camellia sinensis can suffer from algal leaf spot and show some reddish spots. Poor soil drainage, imbalanced nutrition, and exposure to relatively high temperatures and humidity predispose sinensis ot infection by algal leaf spot.

I have not seen fungicides recommended for this (that does not mean there are none); the only suggestion that I have seen is thatt we use good housekeeping/sanitation techniques such as... no overhead watering, disposing of plant debris under the canopy of the bush (throw the debris into a trash can not in a compost pile), water early in the morning, lessen the amount of water if the mulch appears moist all the time, etc. You can also correct drainage problems, allow some separation between the camellia and other plants to improve air flow, do a soil test to check if you have high/low mineral levels, etc.

Thanks luis.

I know that tea leaves are susceptible to fungal leaf diseases, as I have read that they have been spraying tea plants in India and other parts of Asia with copper fungicides like Bordeaux Mixture since the 1800s against leaf spot and leaf blister, so I figured it might be worth a try.

Chris.