| Sitobion avenae (Fabricius) distributed in China wheat-growing regions is the dominant aphidsin the earing stage, which is the most important prevention and research object in wheat products.Chemical control is the primary method in the control wheat aphids, but overusing the pesticide leadto environmental pollution and breakout again. Because the technology of harmless control still needthe more research, it’s urgent to develop the new technology to control wheat aphids. This experimentresearch the wheat aphids death effect by high-temperature-short time in the laboratory and the fields;analysed the aphids physiological causes by aphids respiration; explored the control effect for wheataphids and injures of wheat by high-temperature-short-time. The main results are shown below:1. Detailed experiments were conducted to explore the technique of extremehigh-temperature-short-time on wheat aphids and to measure the mortality rate of Sitobion avenae(Fabricius) in the aphid adults and ny mphs. The results show that the mortality rate increased withincreasing temperature and duration of exposure. The time in wh ich S. avenae (Fabricius) co mp letely deadwas90S at45℃.but it was just5S at70℃. The half-lethal temperature decreased with the prolonging oftreating time and the half-lethal time is decreased with increasing temperature. The half-lethal temperatureand the half-lethal time of aphid and ny mphs were found through the model of logistics under the samecondition.2. Analysed aphid physiological causes from aphids respiration and water loss. The respirationcharacteristic of S. avenae (Fabricius) changed obviously in the high temperature. The respiratory rateincreased compared in the normal temperature. The curve of VCO2arise the spiracle c losing point, heatstupor point, death point and the temperature of the three point is among41℃-43.5℃. Water loss rateof S. avenae (Fabricius) increased with the increasing temperature and S. avenae (Fabricius) will die fromincreasing temperature eventually. The results of S. avenae (Fabricius), Rhopalosipaum padi andSchizaphis gramium are similar.3. Explored the high-temperature-short-time methods to controlled S. avenae (Fabricius) of wheatleaf by aiming aphids or not. The control effect is not effective by not aiming aphids, and the declinerate was only43%in the55℃and15s.The drop-out rate and mortality rate were increased with theincreasing temperature and duration of exposure and the highest drop-out rate is above80%; The aphidswhich did’t drop-out will dead after threedays.The results of using different high-temperature-short-time to control aphids in the in the earingstage show that the aphids decline rate was above90%in the55℃6s treatment or over55℃6streatment. The thousands seed weight of55℃3s treatments,55℃6s treatments,55℃10s treatments,65℃3s treatments were no difference with using imidacloprid treatment, so the results indicate thistreatment have the ability obvious ly maintaining the yield of wheat. Although the65℃6s treatment,75℃3s treatment and85℃3s treatment can lead to high decline rate of aphids, but the ability maintaining the yield of wheat is not ideal.4. The injury of wheat was more serious with increasing temperature and duration of time. We can’tfound obvious injures of wheat leaf with eyes in the45℃3～30s treatments or below55℃10streatments, but the injury of wheat leaf appear at the above65℃with only3seconds. It was noobvious injury of wheatear in the below55℃10s treatments, but above65℃3s treatments can lead toobviously injures or seriously injures. The thousands seed weight were no difference among the below55℃10s treatments or65℃3s treatment, but above65℃3s treatments will reduce the yield of wheat. |
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