The sorghum plant bug Stenotus rubrovittatus (Matsumura) (Heteroptera: Miridae) is a major seed pest of rice in Japan. Male S. rubrovittatus were previously shown to be attracted to traps baited with unmated females. The solvent extract of unmated females was analyzed by GC-MS using HP-INNOWax and HP-5ms columns, and retention index data and mass spectra of peaks detected in the female extract were compared with those of authentic samples. Three compounds, hexyl butyrate (ϭbutanoate), (E)-hex-2-en-1-yl butyrate and (E)-4-oxohex-2-enal, were identified from the female extract. Contents of these compounds in solvent extract of females were ca. 18.6, 8.6 and 1.0 mg/female, respectively. In a field experiment, a blend of three compounds showed potent attractant activity to male S. rubrovittatus, although no binary combinations of the three components were attractive. These results suggested that these compounds are components of the female sex attractant pheromone of S. rubrovittatus.

At tea fields in Shimada in Shizuoka Prefecture, a mating disruptant composed of (Z)-11-tetradecenyl acetate (trade name: Hamaki-con) had been used for controlling Adoxophyes honmai (Yasuda) annually since 1983. In 1986, four years after use of the disruptant was initiated, the disruption percentage of pheromone trap catches was 96%, and a high control effect was observed. However, from 1996 to 1998, 14 to 16 years after treatment was started, the percentages became less than 50%. When the disruptant was applied in other tea fields where it had not been previously used, the disruption percentages were over 99%. These results strongly suggest the possibility that a selection pressure caused by continuous use of the disruptant should have caused the low disruption percentage in Shimada. We propose that the phenomenon be termed "resistance" to a mating disruptant composed of (Z)-11-tetradecenyl acetate in A. honmai. When the sex pheromone blend of A. honmai, 63 : 31 : 4 : 2 mixture of (Z)-9-tetradecenyl acetate, (Z)-11tetradecenyl acetate, (E)-11-tetradecenyl acetate and 10-methyldodecyl acetate (4-component blend), was applied as a disruptant for the "resistance" population, the disruption percentage was 99% and the larval density in the next generation decreased. These results suggest that the 4-component blend is useful as a control tool for the "resistance" population.

Combination treatment may be a more effective and environmentally friendly method for controlling invasive ants than conventional methods. Extermination of ants by insecticidal bait and inhibition of re-infestation by pheromone may be the mechanism of the combination effect. This is the first study to show a significant effect of synthetic trail pheromone on ant population.

Females of the white grub beetle, Dasylepida ishigakiensis, emit a highly volatile, hydrophilic sex pheromone 2-butanol and related compounds. To quantify these compounds, a new method using water to trap them was developed. Vapors of 2-butanol, 2-propanol and ethanol were trapped with water, extracted with an SPME fiber and then injected into GC-MS for analyses. Quantification curves of each alcohol showed good linearity within a certain range. The recovery rate of 2-butanol released from authentic lure tubes was estimated to be ca. 70%. These results indicated that the method tested would be applicable to measure the amounts of volatiles emitted by the beetles. Using this method, it was estimated that field-collected calling females emitted more than 200 ng 2-butanol, ca. 50 ng 2-propanol, and ca. 500 ng ethanol on average in the laboratory. In a second calling trial, however, the amount of 2-butanol emitted by females was reduced to 3% of the amount in the first calling trial. Trace amounts of 2-butanol were detected in volatile samples from males. Because 2-propanol and ethanol were emitted by both sexes in similar amounts, they may not be involved in sexual communication.

No abstract