No abstract

Two major components from pheromone gland extracts of Synanthedon haitangvora females were identified as (Z,Z)-3,13-octadecadienyl acetate (Z3,Z13-18:OAc) and (E,Z)-2,13-octadecadienyl acetate (E2,Z13-18:OAc), and the average ratio of these components was about 1:1. Seven minor components, (Z)-9-hexadecenyl acetate (Z9-16:OAc), (Z)-11-hexadecenyl acetate (Z11-16:OAc), (Z)-9-octadecenyl acetate (Z9-18:OAc), (Z)-13-octadecenyl acetate (Z13-18:OAc), (E,Z)-3,13-octadecadienyl acetate (E3,Z13-18:OAc), (Z,Z)-3,13-octadecadien-1-ol (Z3,Z13-18:OH), and (E,Z)-2,13-octadecadien-1-ol (E2,Z13-18:OH), also were identified from gland extracts. Field tests showed that male S. haitangvora were attracted to Z3,Z13-18:OAc alone, but the maximum number of males was attracted to the binary blend of Z3,Z13-18:OAc and E2,Z13-18:OAc mimicking the blend found in female extracts. The addition of minor components to a 1:1 blend of Z3,Z13-18:OAc and E2,Z13-18:OAc did not increase the numbers of moths captured. The only significant effect of minor components was the strong inhibitory effect of adding Z3,Z13-18:OH to the primary binary blend. Increasing doses of the optimum pheromone blend in the lures from 0.1 to 2.0 mg increased trap catches of male S. haitangvora.

This study was conducted to investigate the characteristics of oviposition and the effect of density suppression by yellow-colored sticky trap on Ricania shantungensis in blueberry. The occurrence of an egg mass of R. shantungensis in the upper, middle and lower region were 56.6~60.2%, 23.8~28.1% and 11.7~19.7%, respectively. The number of egg masses in the branch was investigated. Percentage of the branch with one egg mass was greatest (50.9%) than with two (20.5%), three (14.6%) and over four (14.0%). The effect of yellow-colored sticky trap to reduce the number of R. shantungensis egg masses in blueberry was also investigated. In a month after yellow sticky trap installation, 17.1 adults of R. shantungensis were attracted per trap. Moreover, the number of egg masses on a tree in yellow-colored sticky trap plot was much lower (0.4) than control (1.3). Consequently, this result shows that use of yellow-colored sticky trap may contribute to decrease ovipisotion rate of R. shantungensis in blueberry.

The green peach aphid, Myzus persicae (Sulzer), feeds consistently and regularly throughout all stages of nymphs and adult. That is, honey dew production, which indicates a state of feeding, occurs at regular intervals within a given stage, and moving, which interrupts feeding, tends to occur rarely. We used these behaviors to test whether sound stimuli acted as a stress in this species. We conducted the playback experiment in which acoustic stimuli with a combination of five frequencies (100, 500, 1000, 5000, and 10000 Hz) and three intensity levels (66, 78, 90 dB SPL) were presented to all stages of aphids. Under all acoustic stimuli, honey dew production occurred less often, and moving occurred more often and for longer. The results of two‐way multivariate analysis of variance showed that the stimulus frequency was a significant factor for variation in aphid behaviors in the playback experiment. However, there was no intensity effect on the aphid's behavior. Based on the electrical penetration graph experiment, aphid feeding stopped frequently and lasted only for short durations under acoustic stimuli. The results of both experiments demonstrated that the acoustic stimuli were effective in inducing feeding suppression in this species. Thus, the acoustic stimuli may be a stressor in the green peach aphid. Furthermore, the behavioral bioassay employed in this study may be used to assess the effect of various stressors on aphids.

The plume fruit moth, Grapholita dimorpha Komai, a fruit tree pest occurring in the northeast Asia, was firstly reported to infest apple in Korea in 2009, but its direct damage to other fruit trees has been poorly studied. In this study, we investigated shoots and fruits of both peach and plum trees and compared their damage rates by G. dimorpha to those by G. molesta, a congeneric species. In order to discriminate the two moth species, we developed a molecular diagnosis method using species-specific primer sets on different PCR conditions and distinguished the two species collected from the damaged shoots or fruits. The shoots and fruits of peach were infested mostly by G. molesta. However, in plums, the shoots were damaged by G. molesta and the fruits mostly by G. dimorpha. In addition, these two species showed a clear difference in host preference in fruit damage, where 92.5% of the Grapholita moths collected in peach fruits were identified as G. molesta, but 97.0% of the moths in plum fruits were G. dimorpha. The difference of the damage between the two fruit trees may give important information for monitoring of the two moth species in these orchards.