Sex pheromones of the green mirid, Creontiades dilutus
1Cotton Catchment Communities CRC, Narrabri NSW and School of Rural Science & Agriculture, University of New England, Armidale NSW, Australia and
2Cocoa Research Institute of Ghana, Africa
Correspondence: adelsoc2@une.edu.au
The green mirid, Creontiades dilutus (Stål) (Hemiptera: Miridae) is one of the key species in the “sucking pests complex” in cotton and other field crops such as sunflower, pulses and lucerne in Australia. It is now becoming a significant pest with the reduction of broad-spectrum insecticides and the use of more selective chemicals in transgenic cotton. Semiochemicals like sex pheromones might be useful in managing this pest as monitoring tools, in mating disruption or in an attract-and-kill system. An earlier study on the sex pheromones of the green mirid suggested that hexyl hexanoate might be a component, but it was found in both sexes and no males were attracted to this compound (Miles 1995. Identification, pest status, ecology and management of the green mirid, Creontiades dilutus, (Stål) (Hemiptera:Miridae), a pest of cotton in Australia. PhD thesis, University of Queensland, Brisbane, Australia). No sex-specific compound was detected. We analyzed air collections and whole body extracts of C. dilutus males and females by gas chromatography-mass spectrometry (GC-MS). The sex pheromone was identified as a two-component blend consisting of hexyl hexanoate as the major component and a female-specific compound, (E)-2 hexenyl hexanoate, as the minor component. The latter was detected in the female air collections only. Field trapping experiments were done using Delta traps to compare this two-component blend with either of the single component alone. Only the blend caught males in the traps. Field trials testing various ratios of these components indicated that the optimal ratio was 5:1 of hexyl hexanoate and (E)-2 hexenyl hexanoate. Our preliminary field trials demonstrated that C. dilutus pheromones might be useful monitoring tools of mirid populations and in mating disruption. Both uses might be limited by the volatility of the components. A technique we developed to improve the longevity of the pheromone lures in the field is also described.