The Attraction Of Nine Host Plant Volatiles To Female Bactrocera Dorsalis(Hendel)

The oriental fruit fly Bactrocera dorsalis（Hendel）is a notorious fruit pest.It causes fruit rot through the egg-laying behavior of females,which affects fruit production and quality.Current control method to flies is mainly based on male annihilation techniques by methyl eugenol.As yet,practical strategies for killing females are vague.In this study,the behavioral responses of sexually immature（3 d old）,sexually immature and unmated（9 d old）,and mated（12 d old）females to nine host plant volatiles（esters:ethyl butyrate,methyl caprylate,ethyl caprylate;aromatics:phenyl ethanol,phenyl ethanol,ethyl benzoate;terpenes:β-caryophyllene,α-caryophyllene,3-carene）were determined by a Y-tube.The best substances in each category of volatiles were selected and mixed according to the Table of Orthogonal experiment[L₉（3³）].The attraction of different proportions of the tripled mixtures were determined to sexually immature females.The daily activity law of B.dorsalis was determined in a mango orchard;the attraction of different heights and colors of sticky boards to files was determined.Based on this,three substances selected for the indoor test were mixed by the orthogonal experiment Table L₉（3³）,and the attraction of the mixtures to females was determined in the mango orchard.The attraction of nine volatiles to females was tested respectively in the orchard,then the best substances in each category of volatiles were selected and mixed.The attraction of different proportions of the mixtures to females was determined,then two mixtures were validated in mango and pomegranate orchards.The research results are as follows:1、Laboratory test（1）Choice response of different physiological states B.dorsalis to volatiles from single host plant volatiles.Y-tube was used to test attracting effect nine host plant volatiles to female B.dorsalis in different physiological states.The female insects with different physiological states have different sensitivity and selectivity to the same host plant volatiles.In the esters,0.01μg,0.10μg,1.00μg,10.00μg and 100.00μg ethyl butyrate,1.00μg and 100.00μg methyl caprylate,10.00μg ethyl caprylate showed highly significant attraction for immature females（P<0.01）.Methyl octanoate at 10.00μg showed significant attraction for sexually immature females（P<0.05）;Methyl caprylate at 0.01μg showed significant attraction for sexually mature unmated females（P<0.01）,and ethyl butyrate at 0.10μg,1.00μg and 10.00μg showed significant attraction for sexually immature females（P<0.05）;Ethyl butyrate at 0.01μg and ethyl caprylate at 0.01μg showed significant attraction for sexually mature mated females（P<0.01）,ethyl butyrate at 0.10μg,1.00μg and 10.00μg,and ethyl caprylate at 0.10μg showed significant attraction for sexually mature mated females（P<0.05）.Among the aromatic,0.10μg,1.00μg and 100.00μg of phenylethyl aldehyde showed highly significant attraction for sexually immature females（P<0.01）,0.01μg and 10.00μg of phenylethyl aldehyde and 0.10μg of phenylacetaldehyde showed significant attraction for sexually immature females（P<0.05）;0.01μg,0.10μg,1.00μg and 10.00μg of ethyl benzoate showed highly significant attraction for sexually immature females（P<0.01）,ethyl benzoate at 0.01μg,0.10μg,1.00μg and 10.00μg showed highly significant attraction for sexually immature females（P<0.01）,and phenylacetaldehyde at 0.10μg and phenethyl alcohol at 10.00μg showed highly significant attraction for sexually matured mated females（P<0.01）.Among the terpenes,0.01μg and 1.00μg ofβ-caryophyllene,1.00μg and100.00μg of 3-carene showed highly significant attraction for sexually immature females（P<0.01）,0.10μg,10.00μg and 100.00μg ofβ-caryophyllene,10.00μg of3-carene showed significant attraction for sexually immature females（P<0.05）.β-caryophyllene at 1.00μg,10.00μg and 100.00μg showed highly significant attraction for sexually mature females（P<0.01）.（2）Behavioral responses of sexually immature females B.dorsalis to ternary mixtures.The mixture of phenylacetaldehyde+β-Caryophyllene+ethyl butyrate did not have a significant attraction effect on sexually immature females at the ratios and doses tested indoors（0.01μg,0.10μg,1.00μg,10.00μg,20.00μg,60.00μg and 100.00μg）（P>0.05）.2、Field test（1）Daily activity pattern of B.dorsalis and the attraction of different colors of sticky boards to B.dorsalis.The peak of female activity occurs at 16:30-17:30 and the trough at 06:30-07:30,the peak of male activity occurs at 10:30-11:30 and the trough at 18:30-19:30 in the mango orchard of Yuanjiang County,Yunnan Province.The daily activity of females and temperature were positively related（r=0.957,P=0.001<0.01）,while the daily activity of males and temperature were not related（r=-0.396,P=0.379>0.05）.Four colors of sticky boards（green,blue,yellow and white）are more effective in trapping male insects than female insects when used alone.When comparing the attraction effect of four colors on B.dorsalis,blue sticky boards were the best for attracting males（15.4±2.5 insects/board/h）.When compared the attraction effect of 1.5 m and 0.1 m above the ground,the 0.1 m above the ground was better than 1.5 m above the ground.Combination of different colored sticky boards and mangoes can improve the attraction effect on female insects,white sticky board（8.0±1.3 insects/board/h）.With the increase of the number of sticky boards,the number of insects increased,and the maximum number of female insects was attracted when four white sticky boards were used at the same time（21.0±4.3insects）.（2）The attraction of the mixtures of three substances tested indoors to the females.Comparison of the female attraction of ternary mixtures in Yuanjiang County mango orchards.[0.05 mg,phenylacetaldehyde+β-caryophyllene+ethyl butyrate=5:0.2:5,V/V/V)was the best.（3）The attraction of volatiles from nine host plants to female B.dorsalis.Ethyl butyrate（0.05 mg,6.0±2.1 insects/trap/day）and ethyl benzoate（0.05 mg,4.7±2.1insects/trap/day）showed significant attraction for females,and 0.05 mg of 3-carene showed the maximum attraction（0.05 mg,3.5±2.1 insects/trap/day）.The triple-compound mixtures[ethyl benzoate+3-carene+ethyl butyrate=1:0.2:5（V/V/V）]was the best.Removal of dropped fruits could enhance the effect significantly of the mixture for females.（4）Comparison of the female-attraction of triple mixtures in two orchards.[0.01 mg,ethyl benzoate+3-carene+ethyl butyrate=1:0.2:5（V/V/V）]was the most effective mixture could catch the maximum（25.2±8.2 insects/trap/day）in Yuanjiang County mango orchard,and in Mengzi City pomegranate orchard[0.05 mg,phenylacetaldehyde+β-caryophyllene+ethyl butyrate=5:0.2:5（V/V/V）]could catch the maximum（2.3±0.3 insects/trap/day）.