Disease can’t kill the host or it will perish. It needs the host so it affects only parts of the plant.
In a wet year, there are a lot of “brown spots” on leaves of tea plants. It does not affect young tips that we harvest, but affect mature leaves that produce energy to regrow in following seasons. This is a fungal disease called anthracnose or blight.
Tea plant eventually dry the affected area, drop the part of the leaf and create a hole, leaving the healthy part of the leaf intact. Whether it is plant’s defense mechanism or diesease lifecycle, it teaches an important lesson.
If we are to pursue the way of nature, not spraying to treat the symptom allows us to look for the cause. In this case, wet year, bad drainage of red clay soil, and certain green tea cultivars.