I recently gave a talk on some of my work as a PhD student on experiments manipulating densities of the tea green leafhopper (Empoasca onukii) on tea plants. What the audience liked most, I think, were my methods for finding leafhopper eggs in the field and rearing them in the lab (well, a guest room at a tea farm). You see, leafhoppers (including at least the tea green leafhopper and the small green leafhopper, Empoasca vitis) lay their eggs inside plant tissues, making them impossible to find with the naked eye.
I’m currently in Hangzhou, China at the Tea Research Institute(TRI) for my fourth and last time. It’s bitter sweet (like my favorite teas ;-) ) since I’m both glad to be nearing the end of my PhD, and sad to say goodbye to all the friends I’ve made and a city I’ve really grown to enjoy living in.
Fieldwork This final summer, I’ve been focusing on a few experiments having to do with leafhoppers and their effects on tea chemistry (see the project page for more info).
As part of my fieldwork in China, I collected harvested tea leaves that were damaged by the tea green leafhopper. I want to quantify the amount of leafhopper damage for each harvest. I was able to find several solutions for quantifying holes in leaves or even damage to leaf margins, but typical leafhopper damage is just tiny brown spots on the undersides of leaves. I did find some tutorials on using ImageJ to analyze diseased area on leaves, but found that the leafhopper damage spots were too small and too similar in color to undamaged leaves for these tools to work reliably and be automated.
Eastern Beauty wulong tea is only produced from tea leaves damaged by leafhoppers. The induced volatiles produced by damaged tea plants gives the finished tea a unique flavor. How will leafhopper damage change in a warming climate, and how will that impact tea quality?