Female sex pheromone of oriental tobacco budworm,Helicoverpa assulta (Guenee) (Lepidoptera: Noctuidae): Identification and field testing

Abstract

Analysis of ovipositor washings from virgin femaleHelicoverpa assulta (Guenée) (Lepidoptere: Noctuidae) from Korea by gas chromatography (GC) linked to electroantennography and GC linked to mass spectrometry resulted in the identification of nine compounds, hexadecanal, (Z)-9-hexadecenal, (Z)-11-hexadecenal, hexadecyl acetate, (Z)-9-hexadecenyl acetate, (Z)-11-hexadecenyl acetate, hexadecan-l-ol, (Z)-9-hexadecen-l-ol, and (Z)-11-hexadecen-1-ol. However, ovipositor washings from females from Thailand contained mainly the 16-carbon aldehydes with very small amounts of (Z)-9-hexadecenyl acetate. Field tests conducted in Korea, China, and Thailand indicated that a binary blend of (Z)-9-hexadecenal and (Z)-11-hexadecenal was sufficient for attraction, although the most attractive ratio of compounds varied with location. In Korea a 20∶1 blend of compounds was the most attractive, while in Thailand a 7.5∶1 blend was most attractive. In China both blends of hexadecenal isomers were equally attractive. Addition of the hexadecenyl acetates to the 20∶1 blend of hexadecenals in the ratio of 1∶3.3 increased the trap catch of maleH. assulta compared to lures containing the aldehydes alone in Korea but reduced trap catch in China. Addition of the hexadecenyl acetates to the 7.5∶1 blend of hexadecenals had no significant effect on trap catch in Thailand or China compared to the aldehydes alone. The addition of the 16-carbon alcohols to the aldehydes had a significantly inhibitory effect in all three countries, suggesting they are not pheromone components. Taken together these results indicate thatH. assulta is polymorphic with at least two populations responding to different sex pheromones.

Projections of male-specific receptor neurons in the antennal lobe of the oriental tobacco budworm moth,Helicoverpa assulta: A unique glomerular organization among related species

“…Whereas most of the species rely on cis-11-hexadecenal (Z11-16:AL) as the major pheromone component, H. assulta utilizes this substance as the second component, and cis-9-hexadecenal (Z9-16:AL) as the major one (Sugie et al, 1991;Cork et al, 1992;Park et al, 1994). The optimal ratio between the major and the second principal pheromone component is 20:1 in the Korean population of H. assulta (Cork et al, 1992). …”

Inheritance of Olfactory Preferences I. Pheromone-Mediated Behavioral Responses of <i>Heliothis subflexa</i> × <i>Heliothis virescens</i> Hybrid Male Moths

“…Helicoverpa assulta and Helicoverpa gelotopoeon Z9-16:Ald has assumed a primary role in the pheromone blend [Cork et al, 1992;Cork and Lobos, 2003] and Z11-16:Ald has either been relegated to a secondary role ( H. assulta ) or eliminated from the blend altogether ( H. gelotopoeon ). Interestingly, Z9-14:Ald is inhibitory to H. assulta males and appears to maintain reproductive isolation between this species and several other heliothine species with which its range overlaps to a greater or lesser extent [Boo et al, 1995].…”

Insect semiochemical research in Korea: Overview and prospects

“…1). & Yang, 2000 communication in this species (Cork et al, 1992;Park et al, 1994a). Leaf extracts of Capsicum annum, a major host-plant, evoked significant electroantennogram (EAG) responses in female H. assulta, which could be related to the observation that females showed more actively calling behavior and produced a larger amount of sex pheromone in the presence of the host-plant (Boo and Ahn, 2001).…”

“…Boo, 1988), and histological observation showed the location of a sex pheromone gland at the 8-9th abdominal segments (Moon et al, 1986), which were in close agreement with those reported for other Heliothis/Helicoverpa and other moth species. Shortly after, chemical identification was accomplished in collaboration with British scientists (Cork et al, 1992), and the results were published a year after a Japanese group reported sex pheromone composition of H. assulta in Japan (Sugie et al, 1991). Interestingly, the most abundant sex pheromone component of H. assulta was (Z)-9-hexadecenal (Z9-16:Ald), which was exactly the opposite from other known Heliothis and Helicoverpa species whose major pheromone component was (Z)-11-hexadecenal (Z11-16:Ald).…”

“…Korean agricultural systems are characterized by a relatively small size, crop diversity and often hilly and mountainous terrain. It also became apparent that it is particularly important to identify the appropriate regional pheromone compositions since the pheromone polymorphism among different populations occurs widely, as shown in a number of lepidopteran species (Guerin et al, 1984;Bailey et al, 1986;Cork et al, 1992;Boo, 1998;Han et al, 2001b). Current semiochemical application systems in other countries, which are mostly suitable for much larger, uniform-scale agriculture systems, may need to be modified for optimal efficiency in the Korean environment.…”