Identification And Field Application Of Sex Pheromone Of Adelphocoris Suturalis

The plant bug, Adelphocoris suturalis (Hemiptera:Miridae) is a major insect pest of cotton, Gossypium hirsutum L., in the Changjiang River Region of China. Broad-spectrum pesticide applications had substantial decreased since the commercial cultivation of transgenic cotton from1997because cotton bollworm, Helicoverpa armigera Hubner, was successfully under control. Both A. suturalis nymphs and adults feed on delicate plant organs and buds of cotton, which leads to devastating yield losses and quality decrease in cotton production. Conventional chemical control methods were time-consuming, and often led to undesirable results, such as the development of pesticide resistance and environmental pollution.There is no effective measure to control A. suturalis because of its high mobility and broad host range. Pheromone-baits traps is an effective measure for control and monitoring agricultural and forest pest. We applied the methods of GC, GC-MS, GC-EAD and field trap to identify the main compounents and their proportion of sex pheromone of A. suturalis. Pheromone-baited traps are an effective tool for field control and monitoring A. suturalis, and also potentially to be useful in direct control through the disruption of mating or mass trapping. The main results showed as follows:1. Sexually mature age and the circadian rhythm of sex pheromoneY-tube bioassay results showed that only males possessed strong reponse for odors from sexually mature virgin females. Two-year field trapping experiments indicated that males were a effectively ttracted to4-18-day-old virgin females, and males were attracted to virgin females started17:00, with a peak between19:00-23:00.2. Morphology of the Metathoracic Scent Glands SystemUsed scanning electron microscope (SEM), the morphological structure of the metathoracic scent glands (MTGs) of A. suturalis was observed. The result indicated that MTGs are consist of a reservoir and paired lateral glands. The MTGs possessed two openings extends from a usually depressed channel downwards the middle of metathorax, which known as evaporative area. It was a tongue-like structure covered by bristles and mushroom-shaped cuticular structures3. Behavioral responses of males to volatiles produced in the metathoracic glandsIn GC-MS investigation, differences were found in quantitative and qualitative compositions of the substances between two sexes of A. suturalis. Female were determined19different chemical substances, and21different chemical substances in male,15were found in both sexes. In Y-tube bioassay study, males A. suturalis were strongly attracted to odors from live sexually mature virgin females and females occluded abdomen with paraffin. However, the male gave no or little responses to odors from nymphs and virgin females occluded MTGs.4. Extracts of the active compoundsThe active compounds of sex pheromone of different parts were extracted by different solvents, our GC-EAD recordings showed that the antennae of males of A. suturalis respond to eight active compounds produced by the MTGs of females. But the extracts of headspace absorption were only three same components comparing with the extracts of MTGs.5. Identification and quantitative analysis of the active compoundsEight active compounds were identified using gas chromatography-mass spectrometry (GC-MS). The result showed that active compounds were (E)-2-Hexenal,4-oxo-(E)-2-Hexenal, Hexyl acetate, Pentyl butyrate, Hexyl propionate, Hexyl butyrate, Hexyl hexanoate, Fumaric acid dec-4-enyl propyl ester, respectively. The compounds of female were(E)-2-Hexenal,4-oxo-(E)-2-Hexenal, Hexyl acetate, Pentyl butyrate, Hexyl propionate, Hexyl butyrate, Hexyl hexanoate. The contente was0.178±0.085μg,37.312±8.068μg,0.698±0.332μg,1.699±0.549μg,0.23±0.032μg,46.57±6.893μg,14.025±1.981μg, respectively. However, the compounds of male were4-oxo-(E)-2-Hexenal, Hexyl acetate, Pentyl butyrate, Hexyl propionate, Hexyl butyrate, Hexyl hexanoate, which were9.491±2.405μg,0.0426±0.027μg,2.609±0.549μg,0.416±0.071μg,73.147±25.110μg,0.147±0.064μg respectively.6. Field trap experimentsField trap experiments conducted with five active compounds as single components, with binary blends of there compounds and3multi-components mixtures. However, small number of the male A. suturalis was attracted by single component. The components of4-oxo-(E)-2-hexenal and hexyl hexanoate within a certain range possessed stronger attractiveness to the male A. suturalis. Three multi-components mixtures attract small numbers of male and were unstable.7. Application of the sex pheromone-baited traps in fieldWe estimated the influence of trap color, trap number, trap height, trap placement and distance of trap on the numbers of A. suturalis captured. We found that trap color, trap number, trap placement, and distance had no a significant effect on the numbers of A. suturalis female and male captured. The most A. suturalis were captured by the traps placed at height of150cm from the ground than other height. The study showed that the rhombic trap was more attractive than triangle traps and pentagonal, and catches in trap bait with the polyethylene vials were greater than those in trap bait with a rubber septum.