Behavioral and electroantennographic responses of the tea mosquito, Helopeltis theivora, to female sex pheromones

Abstract

Responses of the tea mosquito, Helopeltis theivora (Waterhouse) (Hemiptera: Miridae), a major pest of tea, to female sex pheromone compounds were measured using wind tunnel and electroantennogram (EAG) bioassays. In the wind tunnel, male tea mosquitoes were found to be most attracted to a dichloromethane extract of the female thorax. Gas chromatography-mass spectrometry (GC-MS) analysis of female thoracic extracts and dynamic head space samples of virgin females showed the presence of five compounds: (Z)-3 hexenyl acetate, (Z)-3 hexenyl butanoate, (E)-2 hexenyl pentanoate, 2,4 dimethyl pentanal, and (E)-2-hexenol. Male tea mosquitoes were attracted to blends of (Z)-3 hexenyl acetate and (E)-2-hexenol in the wind tunnel with a 1:5 ratio eliciting the greatest response. EAG recordings of male antenna confirmed the ability of this blend to evoke antennal responses in male insects. Similarly active EAG responses were recorded toward female thoracic extract and a blend of (Z)-3 hexenyl acetate and (E)-2-hexenol. Behavioral responses of adult males are mediated by a blend of volatile female sex pheromone compounds, (Z)-3 hexenyl acetate and (E)-2-hexenol, at a ratio of 1:5. This female sex pheromone blend may be useful for tea mosquito control and management programs.