Female sex pheromone components of Helicoverpa gelotopoeon: first heliothine pheromone without (Z)-11-hexadecenal

Helicoverpa gelotopoeon Dyar is a very important pest of economic importance on cotton in Argentina. Analysis of female pheromone gland extracts prepared from 1‐ to 2‐day‐old virgin female moths demonstrated the presence of a 1 : 0.84 blend of hexadecanal (16:Ald) and (Z)‐9‐hexadecenal (Z9‐16:Ald), with trace quantities of tetradecanal in some samples, 2.4% of 16:Ald. The average quantity of Z9‐16:Ald extracted per female was estimated to be 33 ng, with a range of 18.9–46.4 ng per female when collected 2–3 h into the scotophase. In field trials conducted in both cotton and tomato crops in Santiago del Estero, Argentina 1 : 1 blends of 16:Ald and Z9‐16:Ald caught significantly more male H. gelotopoeon than Z9‐16:Ald alone, although there was no significant difference between blends containing between a 0.2 : 1 and 2 : 1 ratio of 16:Ald and Z9‐16:Ald. There was no analytical evidence for the presence of (Z)‐11‐hexadecenal (Z11‐16:Ald) in pheromone gland extracts, although this compound has been identified in all female sex pheromones of Heliothinae to date. In field trials, the addition of Z11‐16:Ald at the 1% level to either a 1 : 1 blend of 16:Ald and Z9‐16:Ald or Z9‐16:Ald alone significantly reduced the catch of male H. gelotopoeon. Sympatric Heliothis virescens were not caught in any of the blends tested for H. gelotopoeon, but were caught in low numbers in traps baited with a 4 : 100 blend of (Z)‐9‐tetradecenal and (Z)‐11‐hexadecenal.