Clearwing moths · riparian plantings
Poplar and willow clearwings: a two-species survey that stays readable
Riparian poplar and willow plantings usually carry more than one clearwing. A survey that reports "clearwings" is not a survey — the two species need separate lures and separate records.
Poplar clearwing, Paranthrene tabaniformis, and hornet moth, Sesia apiformis, overlap across much of the range of poplar and willow plantings, and they attack different parts of the tree. One works in the upper trunk and branches, the other at the butt. Blurring them into a single “clearwing” count loses the only information a manager can act on.
Pair the traps
The practical arrangement is a pair of traps on the same tree or adjacent trees: one blend for Paranthrene, one for Sesia, both at the height appropriate to their species. Pairing removes site variation from the comparison and makes the two series directly comparable.
- Paranthrene: upper trunk and scaffold branches, 2–4 m.
- Sesia: butt and lower trunk, 0.5–1.5 m.
- Both: south or west face, on trees with wounds or previous attack.
- Label traps with blend and lot at the trap, not just in the notebook.
Riparian site selection
Clearwing populations follow host density and wounding. Plantations established on ex-agricultural land, blocks with machinery damage, and trees browsed by livestock carry more attack than clean closed stands. Survey effort should follow those risk factors rather than a regular grid — the insect is patchy, and a uniform grid spends most of its traps on empty ground.
Season and record
Both species fly in a single summer generation, with Paranthrene usually a week or two ahead of Sesia. Checks at weekly intervals from early June are enough, provided the dispensers are fresh and the dates recorded. The record should carry, per trap: species targeted, blend lot, height, tree, check dates and catch.
Interpreting a mixed result
A block where Sesia rises while Paranthrene stays flat is telling you something about wounding at the base — often machinery or browsing — rather than about the population as a whole. A block where both rise together usually follows a warm, dry spring and a good emergence. Neither reading is available from a combined count.
Supply
Both blends are supplied against a stated geometry, with per-lot documentation and development quantities for a first season. Because the two compounds are close relatives, order them by name and CAS rather than by description — a substitution here is silent and expensive.
Compounds used in this programme
The materials below cover the blend this programme is usually built from. Where a specification names a different ratio, the components are the same — the ratio is what we quote against.
| Compound | CAS | Class | Recorded targets |
|---|---|---|---|
| (3Z,13Z)-Octadeca-3,13-dien-1-ol | 66410-24-0 | Alcohol | Sequoia pitch moth, Poplar clearwing moth +1 more |
| (2E,13Z)-Octadeca-2,13-dien-1-ol | 123551-47-3 | Alcohol | Hornet moth / Hornet clearwing, Long-legged clearwing moth |
Assay and isomeric composition are stated per lot. Packing starts at 1kg / 25kg / 100kg with development quantities below that.
Questions this programme usually raises
Can I put both blends in one trap?
No. A mixed lure produces a count you cannot assign, and it usually under-catches both species relative to the correct blend.
Do I need traps in every block?
No. Survey the blocks with wounds, previous attack or recent establishment, and use the trap series to decide where to look next.
How do I know a zero is real?
Fresh dispenser, correct height, correct face of the tree, and a check date inside the flight window. If all four hold, a zero is information.