The guava fruit fly, Bactrocera correcta, is one of the major pests affecting mango (Mangifera indica) and guava (Psidium guajava) production in China. The compound β-caryophyllene was identified from the rectal gland extracts of wild B. correcta males and was demonstrated to be a more specific and potent male lure than methyl eugenol (ME) for B. correcta. In order to find potential additional pheromone attractants for the monitoring and mass-trapping of this fruit fly, a series of chemical and behavioral assays were conducted in this study. Ten compounds were identified from the rectal glands of virgin B. correcta females. These compounds consisted of five major compounds (i.e., ethyl dodecanoate, ethyl tetradecanoate, ethyl (E)-9-hexadecenoate, ethyl hexadecanoate, and ethyl (Z)-9-octadecenoate) in high quantities, and other compounds (i.e., octanal, N-(3-methylbutyl) acetamide, (Z)-9-tricosene, ethyl octadecanoate, and ethyl eicosanoate) in trace amounts, while virtually no compounds were found in male rectal glands. The bioassays indicate that female rectal gland extracts are attractive to virgin females and males. Furthermore, a cyclical production of the five major compounds was found, recurring at roughly 10-d intervals with peaks in 10–13-, 25-, and 35-d-old females. Collectively, these results will contribute to the understanding of pheromone communication in B. correcta and may provide important information for improving existing monitoring and control methods for this pest.

Drosophila suzukii (Diptera: Drosophilidae) infests a variety of commercial fruits, including cherries and other soft-skinned fruits. After the cropping season of most cultivated crop hosts, it heavily infests the fruit of a wild host-plant, Osyris wightiana in southwest China. Here, we employ gas chromatography-electroantennographic detection (GC-EAD) together with behavioral bioassays and a trapping experiment to identify volatile semiochemicals emitted by O. wightiana that are involved in D. suzukii attraction. GC-EAD recordings of D. suzukii antenna showed responses to 13 compounds, including α-pinene, 3-methylbutyl acetate, 2-hexanol, E-β-ocimene, Z-3-hexenol, β-caryophyllene, α-humulene, and six unidentified compounds. The flies were attracted by seven individual EAD-active compounds at low doses (0.01 and 0.1 μg), but were repelled at high doses (10 and 100 μg). In a similar manner, a blend of seven EAD-active compounds at low doses (0.1 and 1 μg) was attractive to female flies, but became repulsive at high doses (10 μg). The low dose of the blend was as attractive as the fruit volatiles, although both were less attractive than the fruits. The blend attracted both female and male D. suzukii and other Drosophila flies. The percentage of D. suzukii out of all flies captured by the blend was significantly greater than that captured by the control. These results indicate that the EAD-active volatile compounds emitted by fruits of O. wightiana play an important role in D. suzukii attraction, and have the potential to be used for management of D. suzukii.

The Asian corn borer, Ostrinia furnacalis, is one of the most important pests of maize (Zea mays) in China. However, the mechanism by which intercropping sugarcane (Saccharum officinarum) and maize controls this pest via compounds rinsed from leaf surfaces is still unclear. Electrophysiological and oviposition responses of the Asian corn borer to compounds rinsed from leaf surfaces of sugarcane and maize were studied. Coupled gas chromatographic-electroantennographic detection (GC-EAD) analyses revealed that O. furnacalis responds to 21 compounds, which are present in both the compounds rinsed from leaf surfaces of sugarcane and maize. The effects of these compounds in concentrations of 5 × 10^-3 g/mL or 5 × 10^-4 g/mL on female oviposition behaviour were tested. They were attracted to oviposit on substrates coated with most of the test compounds, except nonanal. It is suggested that the compounds from the leaf surfaces of sugarcane induced O. furnacalis females to oviposit because most of them are similar to maize's leaf surface compounds, which results in a reduction in the number of egg masses laid on maize leaves.

The potato tuber moth Phthorimaea operculella is a serious boring pest of potato. An integrated ecological approach to sustainable pest management is necessary for the control of this species. This study investigated the effects of minced leaves and plant extracts of Eryngium foetidum on the oviposition behavior of PTM females. The behavioral regulatory components of PTM females in response to the extracts were determined using chemical analyses and electrophysiological tests. Individual electroantennographic detection (EAD)-active compounds and mixtures were evaluated using oviposition choice bioassays. The results indicate that minced leaves had a deterrent effect on oviposition. The extracts at low dosages had an attraction effect, while high dosages had a repellent effect on the oviposition of PTM adult females. The dominant compounds of the extracts were trans-2-dodecenal and trans-2-tridecenal and showed EAD activity. trans-2-dodecenal, trans-2-tridecenal and their mixtures showed significant oviposition-repellent effects toward the PTM. The oviposition stimulation indices (OSIs) of trans-2-dodecenal and trans-2-tridecenal were −100% and −94.03% at 10 mg/mL, respectively. The OSIs of mixtures at natural ratios of 10 mg/mL and 5 mg/mL were −95.11% and −90.96%, respectively. The results can be used for the further development of ecological control strategies for this pest species.

This research investigates how fourth-instar larvae of the potato tuber moth, Phthorimaea operculella, respond to plant secondary metabolites (sucrose, glucose, nicotine, and tannic acid) both in terms of gustatory electrophysiology and feeding behavior. The objective is to establish a theoretical foundation for employing plant-derived compounds in potato tuber moth control. We employed single-sensillum recording techniques and dual-choice leaf disk assays to assess the gustatory electrophysiological responses and feeding preferences of these larvae towards the mentioned compounds. Sensory neurons responsive to sucrose, glucose, nicotine, and tannic acid were identified in the larvae’s medial and lateral sensilla styloconica. Neuronal activity was influenced by stimulus type and concentration. Notably, the two types of sensilla styloconica displayed distinct response patterns for sucrose and glucose while they had similar firing patterns towards nicotine and tannic acid. Sucrose and glucose significantly promoted larval feeding, while nicotine and tannic acid had significant inhibitory effects. These findings demonstrate that the medial and lateral sensilla styloconica house sensory neurons sensitive to both feeding stimulants and inhibitors, albeit with differing response profiles and sensitivities. This study suggests that sucrose and glucose are promising candidates for feeding stimulants, while nicotine and tannic acid show potential as effective feeding inhibitors of P. operculella larvae.