A Binary Host Plant Volatile Lure Combined With Acetic Acid to Monitor Codling Moth (Lepidoptera: Tortricidae)

Expression and functional analysis of an odorant binding protein PopeOBP16 from Phthorimaea operculella (Zeller)

Odorant binding proteins (OBPs) are essential proteins in the peripheral olfactory system, responsible for odorant recognition and transport to olfactory receptors. Phthorimaea operculella (potato tuber moth) is an important oligophagous pest on Solanaceae crops in many countries and regions. PopeOBP16 is one of the OBPs in potato tuber moth. This study examined the expression profiles of PopeOBP16. The results of qPCR indicated that PopeOBP16 was highly expressed in the antennae of adults, especially in males, suggesting that it may be involved in odor recognition in adults. The electroantennogram (EAG) was used to screen candidate compounds with the antennae of P. operculella. The relative affinities of PopeOBP16 to 27 host volatiles and two sex pheromone components with the highest relative EAG responses were examined with competitive fluorescence-based binding assays. PopeOBP16 had the strongest binding affinity with the plant volatiles: nerol, 2-phenylethanol, linalool, 1,8-cineole, benzaldehyde, β-pinene, d-limonene, terpinolene, α-terpinene, and the sex pheromone component trans-4, cis-7, cis-10-tridecatrien-1-ol acetate. The results provide a foundation for further research into the functioning of the olfactory system and the potential development of green chemistry for control of the potato tuber moth.

Research of Synergistic Substances on Tobacco Beetle [Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae)] Adults Attractants

In this study, four kinds of chemical substances (2,3,5,6-tetramethylpyrazine, β-ionone, citronellal, and paeonol), three kinds of plant essential oils (tea tree essential oil, lavender essential oil, and myrrh essential oil), and their combinations were selected to explore their synergistic effects on tobacco beetle [Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae)] adults by the behavioral test and laboratory simulation test. Behavioral test results showed that some of the combinations revealed a synergistic effect on tobacco beetle adults, especially the sexual attractant +2,3,5,6-tetramethylpyrazine + β-ionone + citronellal + paeonol (SABCD, one portion of sexual attractant, and 1 mg/L synergistic substances) combination and the food attractant +2,3,5,6-tetramethylpyrazine + paeonol (FAD, 1 ml of food attractant and 1 mg/L synergistic substances) combination showed the best behavioral effect on tobacco beetle adults with average dwell times of 120.97 and 126.74 s, respectively, compared to those of other combinations. Meanwhile, SABCD had the highest selection rate [89.47%, about 1.5 times that of the sexual attractant (S)] on tobacco beetle adults compared with those of other combinations. In addition, laboratory simulation test results showed that the SABCD combination had the highest average selection rate (37.31%, about 2 times that of S) on tobacco beetle adults at 1 mg/L. However, our results showed that there was no significant difference in the indoor simulation results of food attractant synergistic substances. Our results will provide guidance for the development of new pesticides for tobacco beetle adults.

Monitoring Chilecomadia valdiviana (Lepidoptera: Cossidae) Using Sex Pheromone-Baited Traps in Apple Orchards in Chile

Simple Summary

A series of experiments were carried out to evaluate the efficacy of trap type, sex pheromone (Z7,Z10-16:Ald) dose, and trap height on attraction to males of Chilecomadia valdiviana (Philippi) (Lepidoptera: Cossidae) in the canopy of apple orchards in Chile. Based on trap catches and relative costs, we propose that bucket traps (6 L) baited with 300 μg of sex pheromone, regardless of canopy height, are suitable for male mass trapping, while delta traps baited with 300 μg of sex pheromone are adequate for monitoring of male flight.

Abstract

Chilecomadia valdiviana (Philippi) (Lepidoptera: Cossidae) is a native xylophagous pest in apple orchards in Chile. A series of experiments evaluated the efficacy of trap type, sex pheromone (Z7,Z10-16:Ald) dose, and trap location in the apple tree canopy on trap catch of male adults. Bucket traps (6 L), with and without roof and cross vane spacers, together with bucket traps (20 L) without roof and spacers, showed higher catches among the four types of traps evaluated. In a second experiment, the UNI-trap and Delta trap showed higher catches than Multipher, wing, and bucket traps (6 L). Male catches were not affected by height when tested at 0, 1.5, and 3 m in the canopy. A 300 µg dose of Z7,Z10-16:Ald showed higher catch than the control treatment. This dose allowed monitoring of male flight of C. valdiviana for at least five weeks in apple orchards in Chile. Based on relative trap costs, we propose the use of 6 L bucket traps for male mass trapping, while Delta traps can be used for monitoring of male flight. We found that male flight of C. valdiviana occurred mainly from mid-August to late November, reaching its maximum in mid-September.

Caterpillar-induced plant volatiles attract conspecific adults in nature

Plants release volatiles in response to caterpillar feeding that attract natural enemies of the herbivores, a tri-trophic interaction which has been considered an indirect plant defence against herbivores. The caterpillar-induced plant volatiles have been reported to repel or attract conspecific adult herbivores. To date however, no volatile signals that either repel or attract conspecific adults under field conditions have been chemically identified. Apple seedlings uniquely released seven compounds including acetic acid, acetic anhydride, benzyl alcohol, benzyl nitrile, indole, 2-phenylethanol, and (E)-nerolidol only when infested by larvae of the light brown apple moth, Epiphyas postvittana. In field tests in New Zealand, a blend of two of these, benzyl nitrile and acetic acid, attracted a large number of conspecific male and female adult moths. In North America, male and female adults of the tortricid, oblique-banded leafroller, Choristoneura rosaceana, were most attracted to a blend of 2-phenylethanol and acetic acid. Both sexes of the eye-spotted bud moth, Spilonota ocellana, were highly attracted to a blend of benzyl nitrile and acetic acid. This study provides the first identification of caterpillar-induced plant volatiles that attract conspecific adult herbivores under natural conditions, challenging the expectation of herbivore avoidance of these induced volatiles.