Leafhopper feeding damage (zhu xian)
A small green leafhopper feeds on the growing shoot and the plant answers. The answer is the raw material: shoots that have been fed on are picked in that state, and a tea made from undamaged leaf on the same bush is a different tea.
The categories this step defines
In tea, processing is not a modifier applied to a category — it is what creates the category. These are the types that exist because this step exists.
- Oolong — Deliberate bruising to initiate edge oxidation, halted partway, frequently followed by roasting.
What it is
Tea green leafhoppers of the genus Empoasca feed by piercing young shoots and drawing sap. Fed-on shoots stop growing properly: they stay small, the margins curl and brown, the leaf yellows, and a field at the right stage looks damaged rather than healthy. The wounded plant responds by producing volatile compounds, and those volatiles are what the finished tea is bought for — the honey-and-ripe-fruit register of a bug-bitten oolong is a wound response, not a manufacturing decision. Because the insects must be present and active, the field cannot be sprayed, which puts the whole crop at their disposal in both directions: too few and there is no honey note, too many and there is no crop. Yield falls sharply — a bitten shoot weighs a fraction of an unbitten one — and the timing cannot be scheduled, because it depends on an insect population, a season and the weather rather than on a calendar. TeaHQ records this as a processing step and not as a growing condition on purpose. It happens before the pluck, it is not performed by anyone, and it is still the operation that defines the product, which makes it the sharpest available test of what a processing table is actually for.
Also transliterated as: zhu xian, zhuxian, xiao lü ye chan.
What it does to the leaf
Punctures the leaf and stem tissue of a living shoot repeatedly over days or weeks, arresting its growth and inducing the plant's own volatile response in the standing crop, so that the leaf arrives at the factory already chemically altered.
What it does to the cup
Associated with the honey, ripe stone fruit and muscat register of bitten oolongs and of the honey-fragrance black and oolong teas of Taiwan. The character is present in the leaf before manufacture begins, which is why it survives processing routes as different from one another as a heavily oxidised oolong and a black tea.
Variants that matter
Ways this step is carried out that produce genuinely different results, rather than regional names for the same thing.
- Summer bitten oolong
- The classic case. Leafhopper pressure is highest in the warm months, which inverts the usual seasonal hierarchy: this is one of the few Chinese-tradition teas whose best material is a summer pluck.
- Honey-fragrance black tea
- The same bitten intake taken down a black tea route instead of an oolong one. The wound-derived aroma is a property of the leaf, so it carries across, which is the clearest demonstration that this step is upstream of the category.
- Unbitten lots from the same garden
- Bitten and unbitten shoots are separated at or after picking because they cannot be made into the same tea. What looks like a grading decision is really the point at which two different products divide.
Where this gets misdescribed
That the insect adds something to the leaf, or that the tea is fermented by it. Nothing is added and nothing microbial is involved: the plant is responding to being wounded, in the same broad way that a shaken oolong leaf responds to being bruised in a drum. The other misreading runs the opposite way — that bug-bitten is a marketing term rather than a physical state — when the yield loss it costs a grower is the strongest evidence that it is not.
Other steps at the Bruising stage
- Bruising (shaking) — Deliberate, repeated agitation that damages the leaf edges so oxidation begins there and nowhere else.
Teas that go through this step
Sources
- TeaHQ editorial synthesis — TeaHQ
This page is TeaHQ’s own synthesis of well-attested production practice. No external technical document stands behind it, so it describes what producers do rather than asserting measured process parameters.