Influences Of Diffenent Pesticides On The Insects And Physiology And Biochemistry Of Tobacco

This trial studied the effects of four kinds of conventional pesticides of farmland (the Omethoate 40% EC and acephate 30% EC and dilution 10% Imidacloprid and 200g/lKangfuduo) and two kinds of botanical pesticides producted by myself(botanical pesticides 1 and botanical pesticides 2)on the insects(Myzus persicae(Sulzer) and Helicoverpa assulta (Guenee))and physiology and biochemistry of tobacco. It aimed to explore the physiological mechanisms of inhibiting and promoting functions after spraying pesticides and select a kind of the best one, which could kill the insects of tobacco effectively and be safe to the tobacco growth. The results showed as followings:1. Two kinds of botanical pesticides with good control effect and long persistent period and security to natural enemy, especially botanical pesticides 1 had better effect to control Myzus persicae(Sulzer)and Helicoverpa assulta (Guenee) in tobacco field than botanical pesticides 2 and conventional pesticides, which could be used as a new medicament in the large-scale popularization. The suitable diluent was 500 and the application of Helicoverpa assulta was 2-3 age period of peak。Three kinds of conventional pesticides(the Omethoate 40% EC and acephate 30% EC and dilution 10% Imidacloprid )also had good effect to control Myzus persicae and Helicoverpa assulta and used in the farmland. However, attention should be paid to the rotation of different types of chemical pesticide use, delay the emergence of resistant pests.2. Botanical pesticides 1 could increase the plant height and stem thickness and leaf number and the largest leaf area and conventional pesticides decrease the largest leaf area compared with the control. And botanical pesticides 1 was the best to increase the LAI and dry matter accumulation among all the treatments. The IAAO activity、the Chlorophyll contents and the Chlorophyll a/b of flue-cured tobacco leaves were affected in the pre-application but recovered to control level at 20 day. The IAAO activity was increased and the Chlorophyll contents and the Chlorophyll a/b were decreased after accumulated spraying pesticides three times.3. Both the Inv and NRA activity of flue-cured tobacco leaves were decreased after spraying pesticides, and the reduction of after accumulated spraying pesticides three times was greater than spraying pesticides once.4. Both the PAL and PPO activity of flue-cured tobacco leaves were increased in the pre-application, and then with the spraying time, began to decline after spraying pesticides once. Accumulated spraying pesticides three times could increase the PAL and PPO activity and decrease the total phenols and flavonoid contents.5. The MDA contents of flue-cured tobacco leaves were increased significantly after accumulated spraying pesticides three times and the impact were more than spraying pesticides once. Spraying pesticides could increase the SOD and POD and CAT activity of flue-cured tobacco leaves. Spraying conventional pesticides once could decrease the GSTs activity, but spraying botanical pesticides not,and accumulated spraying pesticides three times could increase the GSTs activity.6. The economic character of flue-cured tobacco were improved after spraying pesticides during the tobacco growth. Compared with the control, spraying pesticides could improve the contents of the weight of per leaf and balanced water ratio and tensile strength and filling value of of middle tobacco leaves; lower the thickness of leaves and midrib ratio and weight of per area; decrease the total N and nicotine and reducing sugar and Cl- and the ratio of total N and nicotine; raise the total sugar and K+ and the ratio total sugar and nicotine and the ratio K+ and Cl-; and also raise the contents of petroleum ether extract and the neutrality volatile aroma of middle tobacco leaves.On the whole, the botanical pesticides 1 had the best control effect to the insects of tobacco field and the lest impact on the growth and could improve the yield and quality of flue-cured tobacco, followed by botanical pesticides 2, dilution 10% Imidacloprid, acephate 30% EC, Omethoate 40% EC。...