| Aphids cause much damage to Chinese cabbage in north China. Over reliance on pesticides has negative effects, for example the environment, natural enemies and food safety. Large enviromental and human health costs that compel researchers to seek alternative management tactics and technology for aphids control. The biggest strength of biological control is no polluted to environment. This is incomparable to the other tactics for disease and pests control. Own secretions of aphids can do some effects to themselves and their natural enemies. The specificity and bioactivity of aphids own secretions are strong, and it is also safe to the no target creature. So it will be the very important direction of green pesticide. The component of aphid alarm pheromone, E-β-Farnesene (EβF); sex pheromone, Z,E-Nepetalactone (NEP) and Honeydew (HON) are very important secretions of aphids. EβF which interferes with aphid host locating and feeding, can strong attract natural enemies in laboratory. The component of aphid Honeydew and sex pheromone can also attract natural enemies. This maybe can provide theoretical basis for the cabbage aphids control. To understand the effects of EβF,HON and NEP to aphids and their natural enemies. This article tests the olfaction of aphids and natural enemies ladybeetles, Syrphidaes to the three molecules using olfactometer and wind tunnel in laboratory. And we also released in the fields to test the effects of the combination of E-β-Farnesene and low concentration imidacloprid, and the effects of E-β-Farnesene,Honeydew and Nepetalactone. The research of the combination of E-β-Farnesene and low concentration imidacloprid was established by four treatment field plots: (a) Control; (b) EβF released; (c) Low concentration imidacloprid sprayed (LCIS); (d) LCIS and EβF released. We selected 5 m, 10 m, 15 m and 20 m away from the releaser to investigate the related aphid data.1. Effects of Z,E-Nepetalactone and Honeydew on aphids and natural enemiesIn the olfactometer experiments, HON 4 (100μg/ml) and NEP (10μg/ml) can do significant influence to the duration time of aphids. HON 1 (10μg/ml), HON 2 (1μg/ml),HON 4 (10μg/ml)and NEP (1μg/ml) can do significant influence to the duration time of ladybeetles. In the wind tunnel, the Asian lady beetle Harmonia axyridis Pallas was significantly attracted by the NEP at a dose of 1 mg, the aphid Myzus persicae (Sulzer) and the hoverfly Episyrphus balteatus did not show any behavioural response to this volatile compound. The results in the fields is: the order of ladybeetles on the plants is Honeydew 2 (10.7) > Nepetalactone (9.7) > Honeydew 1 (5.3) > CK (4.7); mummified aphids: Nepetalactone (430) > Honeydew 1 (338) > Honeydew 2 (236) > CK (53); Cabbage aphids: Honeydew 1 (4430) < Honeydew 2 (5852) < Nepetalactone (6509) < CK (6688).2. Effects of E-β-Farnesene on aphids in the fieldThe result showed that, at 5 m, alatae and apterae were significantly higher in plots (c) than (d) both in 2009 and 2010. There were significant differences for apterae between plots (a) and (b) in 2009 (P < 0.05). It was significantly different in the interactions of treatment and distance for apterae (P < 0.01) in the two years. There were significant differences in the interactions of EβF and LCIS for apterae at 5 m, 10 m, 15 m (P < 0.05) in 2009, 5 m (P < 0.05) in 2010; for alatae 5 m, 10 m (P < 0.05) in 2010. The relationships between deterrent rate (Y) and distance (x) from the releaser were simulated by the cubic models, in EβF without LCIS plots: Y = 327.220 - 0.153x3 + 6.344x2 - 82.254x, F = 3.687, P = 0.062, R2 = 0.580; In EβF with LCIS plots: Y = 304.640 - 0.195x3 + 6.866x2 - 74.766x, F = 13.149, P = 0.002, R2 = 0.831.3. Effects of E-β-Farnesene on natural enemies in the fieldLadybeetles on Chinese cabbage leaves were significantly higher in EβF released plots than in control plots (2009: F1,4 = 0.000, P < 0.05; 2010: F1,4 = 7.185, P < 0.05). Aphidiidae were significantly higher in EβF released yellow traps than in control yellow traps (2009: F1,4 = 1.538, P < 0.05; 2010: F1,4 = 0.643, P < 0.05). There were significant differences in mummified aphids (P < 0.01) and spiders (P < 0.05) on cabbage plants, ladybeetles in traps (P < 0.01) between the two years. But no significant differences were detected in the interactions of different treatments and the two years for all natural enemies. Importantly, significantly low aphid densities were found in EβF released plots (2009: F1,4 = 1.454, P < 0.01; 2010: F1,4 = 0.491, P < 0.05).The behavioral experiment of aphids and natural enemies in laboratory show that some doses of E-β-Farnesene,Z,E-Nepetalactone and Honeydew can do some effects on the behaviour of aphids and natural enemies. The field experiments show that secretions of aphids can do some effects on aphid control, especially in 5m. But using secretions of aphids solely, the effects is very little. Some secretions together with low concentration insecticide is a good solution, it can reduce the aphid population effectively, and also can reduce the negative influence by chemical pesticide.
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