Synthesis and Biological Testing of Ester Pheromone Analogues for Two Fruitworm Moths (Carposinidae)

Synthesis and bioactivity studies of the potato tuber moth, Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae) sex pheromone analogs

BACKGROUND

Potato (Solanum tuberosum L.) is a staple food crop globally, but its production is consistently threatened by diseases and arthropod pests like the potato tuber moth, Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae). Phthorimaea operculella is often controlled by chemical applications. Sex pheromones have been used to detect, monitor, or control agricultural pests. Phthorimaea operculella sex pheromones mainly contain two chemical structures, 4E,7Z-trisadene-1-ol acetate and 4E,7Z,10Z-trisadene-1-ol acetate. However, the pheromone analogs are expected to act as mimics, synergists, antagonists, and inhibitors for pheromones and can be synthesized at a large scale.

RESULT

In this study, a total of 11 sex pheromone analogs of P. operculella were designed and synthesized. Results showed that the antennae exhibited a concentration-dependent response to sex pheromones and their analogs. Different analogs and dosages had significant effects on the electrophysiological response of the antennae. In the field trials, when used alone, A6, B3 and B5 exhibited significant trapping effects in tobacco and potato fields. When used alternately with sex pheromone components, the analog B3 had significantly higher trapping effects in both tobacco and potato fields compared to the control, while combinations containing fluorinated analogs showed lower trapping effects.

CONCLUSION

In summary, the use of sex pheromone analogs holds great promise for integration into pest management programs. Further investigation to fine-tune dosage and duration for optimal use is still needed. © 2024 Society of Chemical Industry. Published by John Wiley & Sons Ltd.

Structure, Synthesis, and Bioassays of Sex Pheromone for Pyrausta machaeralis (Lepidoptera: Crambidae)

The leaf skeletonizer, Pyrausta machaeralis (Lepidoptera: Crambidae), is a serious insect pest of teak (Tectona grandis) in China. The application of insect pheromones is widely applied as an environmentally friendly technology for integrated pest management (IPM). In the present study, crude extracts of sex pheromone glands of calling P. machaeralis females were collected and then analyzed using gas chromatography/electroantennographic detection (GC/EAD) and gas chromatography-mass spectrometry (GC-MS). The combination of infrared spectroscopy (IR) and nuclear magnetic resonance (NMR) spectrometry was used for structure identification. Afterward, their electrophysiological and behavioral activity was evaluated in the laboratory and field. Herein, we eventually determined two active components, E-11-tetradecenyl acetate (E11-14:Ac) and Z-11-tetradecenyl acetate (Z11-14:Ac), at a ratio of 96:4, as the sex pheromone of P. machaeralis. The identification of sex pheromones would facilitate the development of efficient strategies for monitoring and controlling the field populations of P. machaeralis.

Development of a New Sex Attractant via the Peripheral Coding of Pheromones in Mythimna loreyi

Sex pheromones play an essential role when moths are searching for mates. Male olfactory receptor neurons (ORNs) are the primary determinant during peripheral pheromone recognition. Here, we identified the sex pheromones of a global agricultural pest, Mythimna loreyi, using gas chromatography coupled with mass spectrometry and electroantennographic detection. Nine pheromone components were identified, including (Z)-9-tetradecen-1-yl acetate (Z9-14:OAc), (Z)-7-dodecen-1-yl acetate (Z7-12:OAc), and (Z)-11-hexadecen-1-yl acetate (Z11-16:OAc), and the first two elicited electrophysiological activities in the male antennae. Trichoid sensilla were classified into four functional types on the basis of neuronal responses to pheromones by single sensillum recording. Five functional ORNs were involved in recognizing pheromones and pheromone analogues. Finally, a field bioassay revealed that a blend of Z9-14:OAc, Z7-12:OAc, and Z11-16:OAc at a ratio of 100:8.8:19.7 was highly efficient for trapping males. Our results uncover the pheromone recognition mechanism in M. loreyi and provide a novel angle for developing efficient sex attractants of pests on the basis of screening the peripheral olfactory neurons.

Synthesis and Electrophysiological Testing of Carbonyl Pheromone Analogues for Carposinid Moths

Sex pheromone analogues were synthesized and tested on two pest carposinid moth species: the guava moth, Coscinoptycha improbana, and the raspberry bud moth, Heterocrossa rubophaga. The pheromone analogues used for the electroantennogram testing included (Z)-11-methylenenonadec-7-ene, (Z)-nonadec-12-en-9-amine, (Z)-11-methoxynonadec-7-ene, (Z)-1-(octylsulfinyl)-dec-3-ene, and (Z)-nonadec-12-en-9-ol. An imine analogue, N-((Z)-nonadec-12-en-9-ylidene)cyclopropanamine, was also synthesized but was too unstable for testing with the moths. None of the analogue compounds elicited significant responses from the male moth antennae.