Jassid-damaged teas: Why are they different?

[mbanu]

Oriental Beauty oolong and some varieties of Darjeeling black tea claim that their unique aroma comes from being attacked by the green fly (leaf hopper, tea jassid, empoasca flavescens)... but in general insect damage decreases tea quality... Is jassid damage truly different, or are these teas engaging in a bit of sly marketing?

[Proinsias]

From what I gather the insect bite starts an oxidation process which alters the taste of the tea, I've also heard it said that organic oriental beauty invites more insect bites.

Here's an old blog post by Stephane Erler on Oriental Beauty which might be of interest.

[teaisme]

Is jassid damage truly different, or are these teas engaging in a bit of sly marketing?

No I don't think its sly marketing but I don't recall ever tasting tea that was severely bitten by other insects so I'm just giving the farmers the benefit of doubt that they aren't bsing.

Here is hojo's guess at what is going on.

The mechanism of formation of the mysterious fragrance is yet to be fully revealed. We assume that the tea leaves attacked by these insects will subsequently produce some kinds of antibody. Usually the antibody of plant is called Phytoalexin. It is known that there is a type of Phytoalexin which gives a fruity aroma. It is a small molecular substance called terpenoid. We wonder if this substance has anything to do with the flavor of Oriental Beauty.

I wonder if they try to transplant jassids onto tea fields that do not have them in abundance naturally. Would be interesting to see if this is common practice to reinforce more bites. Of if they spray the leaves with certain things to attract more jassids, like a light mist of fruity apple/peach water.

[wyardley]

I usually consider it a good thing if I see some (larger) insect bites on tea. It doesn't prove that pesticides weren't used at all, but I always consider it a good sign to see a few.

[gingkoseto]

I think Hojo's guess is quite reasonable. And oxidation mechanism may play a role too.

I don't think the farmers need to intentionally induce the "jassid", as they may not need invitation anyway

Last year, I got some "jassid-damaged tea" (but not oriental beauty) from Taiwan which was supposed to be harvested in early summer but ended up being harvested in April. According to the farmer, due to the cold early spring and delayed warm days, when smaller insects all came out, their predators, the larger ones were not out yet. Then there were suddenly a lot of leaf eaters. So they had to harvest the tea earlier, otherwise there wouldn't be much left to harvest. The tea turned out pretty good

By the way, can somebody verify what the "jassid" in Taiwan is? Once I got the name on a Taiwan gardening website Jacobiasca formosana, but don't know if that's it. In Chinese name it's called some sort of "cicade" but it's of tiny size.

[teaisme]

Jacobiasca formosana, but don't know if that's it. In Chinese name it's called some sort of "cicade" but it's of tiny size.

Think thats it. So.....

Cicadellidae Empoasca Jacobiasca formosana?

...I am just piecing pieces of info together (no clue really, but that is my guess after some meandering through google, Cicadellidae being the family, Empoasca/Empoascini being the tribus ,Jacobiasca being the genus, and formosana being species?)

http://www.catalogueoflife.org/details/ ... id/9344865
http://ctap.inhs.uiuc.edu/dmitriev/taxa ... ura&lng=En

You think that sounds right? I don't know a thing about biology or classifications in biology, but it was fun trying to learn !

And found this, supports what hojo was saying, but going into little more specifics

We found that the flavor is attributable to monoterpene diol and hotrienol, whose production is specifically induced after the suction of phloem juice by insects. In addition, each preparation step of "Oriental beauty" is regarded as mechanical stresses for plant, such as UV - light, draught, and wounding, by which many complex secondary metabolites are also produced in leaves.

Plants have highly flexible and sophisticated tolerance mechanisms for various environmental stresses, e.g. wounds, pathogens, and draught, since they have sessile life where they were germinated. Terpenoids of low molecular weight are plant - derived volatiles and play important and specific roles in attracting pollinators, protecting plant bodies from pathogens, and also drawing attention of natural enemies of herbivores by their attack.
In this study, we characterize the biosynthetic regulation and accumulation of terpenoid metabolites by use of tea plant (Camellia sinensis) as a model, which produces various aroma compounds during the process of tea production. Those compounds are, from the viewpoint of plant physiology, known as being secondary metabolites specifically produced by wound, UV, and draught stresses. We are also aiming to provide the knowledge of this study for the application studies on molecular breeding of tea tree or food technology of tea products.

http://iss.iae.kyoto-u.ac.jp/iss/eng/re ... azaki.html

This has got me wondering, has anyone tried the delicious looking stuff from houde...now those are some serious bites!
http://www.houdeasianart.com/index.php? ... ts_id=1384