Cornicles

The cornicles are highly variable in shape, colour and length. They are a feature commonly used as identification criteria for adult forms of different species. You can therefore find cornicles in various shapes and sizes: short cone-shaped (A), swollen (B), or straight (C), medium-sized ones that can be swollen (D) or straight (E), long ones (F) or even very long straight (G) or swollen ones (H). In certain species, the cornicles are reduced to a pore, in others even completely absent. Cornicle shape and form can also vary within the same species, according to the stage or morph.

 A : Cinara spp.

B : Brevicoryne brassicae

C : Rhopalosiphum padi

D : Megoura viciae

E : Sitobion avenae

F : Aulacorthum solani

G : Acyrthosiphon pisum

H : Wahlgreniella nervata