| Potato Solanum tuberosum (Solanales:Solanaceae) is one of the most important crops in the world. The damages of aphids have caused huge economic losses for a long time. Myzus persicae and Macrosiphum euphorbiae are important pests on the potato plants.They can not only induce direct damages by feeding on phloem but also transmit phytovirus as efficient vectors. At present, the unreasonable use of chemical pesticides to control aphids has more and more negative effects on environmental pollution, production and lives. It’s inevitable that the biological control will substitute pesticides in the integrated pest management. Insect semiochemicals have been recognized as potential, beneficial, sustainable and environmental alternative tools for the control of pest. Among semiochemicals relevant for aphids control, aphid alarm pheromone E-β-farnesene (EβF) is among the most promising, which interferes with aphid host locating and feeding, and can also attract natural enemies. At the same time, it also also provides a new train of thought for the control of virus diseases transmitted by aphids. To understand the effects of EβF on the population and dispersal of aphids and their natural enemies in the potato fields, and the effects of EβF on the virus transmission efficiency of apterous aphids, we designed the experiments. In this paper, the impacts of EβF release on the population of major aphids and natural enemies on potato plants were studied in the field. While under laboratory conditions, effects of EβF on dispersal and virus transmission efficiency of apterous M. persicae and M. euphorbiae were investigated. The research in the field was established by two treatment field plots:Control (CK) and EβF released (EβF). We selected1m,5m and10m away from the releaser to investigate the related aphid data. For the investigation of natural enemies, we took a random sample survey around the yellow traps. The laboratory experiments also had two treatments:Control (CK) and EβF (EβF) released to study the dispersal and virus transmission efficiency of apterous M. persicae and M. euphorbiae. The main results are as following:1. Effects of E-β-Farnesene on aphidsDuring the two years, the EβF treatment reduced the population of alatae and apterae significantly (2012:Palatae<0.01, Paterae<0.05;2013:P<0.01). The distance affected the population of alatae and apterae significantly (2012:Paiatae<0.05, Paterae<0.01;2013:Palatae <0.01, Papterae<0.05). In2012, the number of alatae and apterae was significantly higher at10m away from yellow traps than at1m and5m. In2013, the number of alatae and apterae was significantly higher at5m and10m away from yellow traps than at1m. The interaction of treatment and distance did not have significant effect on the population of aphids. In2012, the population of alatae in yellow traps were significantly lower when treated with EβF.2. Effects of E-β-Farnesene on natural enemiesIn2012, EβF treatments significantly improved the population of mummified aphids (F=0.193, P=0.033) and ladybirds (F=0.275, P=0.023) on the plants. The population of hoverflies (F=0.305, P=0.001) and parasitoid (F=0.667, P=0.004) were significantly higher in EβF treatment in the yellow traps. In2013, EPF treatment significantly improved the population of ladybirds on the plants (F=0.506, P=0.000). The population of ladybirds (F=0.137, P=0.021) were significantly higher in EβF treatment in the yellow traps while there was no significant difference for hoverflies (F=0.521, P=0528) and parasitoid (F=0.746, P=0.210).3. Effects of E-β-Farnesene on dispersal of aphidsSignificant lower population in M. persicae and M. euphorbiae was determined when EβF was released at releaser (0cm) and select plant (10cm and20cm)(M persicae:F0=0.643, P=0.000; Fl0=0.122, P=0.000; F20=0.410, P=0.024; M. euphorbiae:Fo=0.184, P=0.013; Fio=0.238, P-0.002; F20=0.374, P=0.030). According to the association between deterrent rate of EβF and distance, the quadratic regressions was established with the following equations:Y=87.870+1.316x-0.162x2(P=0.003, F=8.012and R2=0.857), for M. persicae and:Y=63.056+4.558x-0.304;c2(P=0.002, F=21.180and R2=0.876) for M. euphorbiae.4. Effects of E-β-Farnesene on virus transmission efficiency of aphidsAt10cm and20cm away from EβF releaser, transmission efficiency of PVY allowed to observe significant higher on infochemical release for M. persicae (Fio=0.184, P=0.013; F20=0.205, P=0.003) and M. euphorbiae (F,o=0.089, P=0.025; F20=0.184, P=0.013). Switching to PLRV, absolutely no effect was determined on PLRV transmission efficiency for both M. persicae (Fl0=0.184, P=0.519; F20=0.230, P=1.000) and M euphorbiae (F10=1.000, P=1.000; F20=1.000, P=0.519).The behavioral experiment of aphids and natural enemies in the field and laboratory show that some doses of EβF can do some effects on the behaviour of aphids and natural enemies. The field experiments show that EβF can do some effects on aphid control, especially in5m. But using EβF to control the virus diseases transmitted by aphids, the effects is very little. |
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