Research On The Nitrate And Nitrite Contents In Vegetables And Using Bio-pesticides To Control Pests And Diseases

Based on comprehensive investigation of pollution-free vegetables in Lanzhou city, the heavy metal contents, nitrate accumulation and remains of pesticides in vegetables were analysised. The results showed that the heavy metal contents and nitrate accumulation in vegetables were lower than the safe standard, but the remains of pesticides was severe. In review of the results, experiments of using bio-pesticides to control the main pests and diseases in several major vegetables have been conducted. In the same time, application and dissemination have been carried out according to the results.1 Experiments in laboratory indicated that Yinguo, Guweishi, polyoxin and Jiajituobujin were good in controlling the pathogen(Cladosporium fulvum Cooke) of tomato leafmold, matrine followed, but BailiXiang oil almost did not work. 10 days later after inoculation, the conobium diameter of the bacterium was 14.6mm, 15.6mm, 16.7mm, 14.5mm, 26.5mm and 31.9mm respectively, while the conobium diameter of CK was 34.1mm. Experiments in field indicated that 5 kind of bio-pesticides(kasugamycin, polyoxin, Wuyijunsu, Guweishi, Yinguo) had about the same good effect as the chemical pesticide Daisenmengxin in controlling the disease of tomato leafmold. 18 days later after sprayed, the relative controlling effect was 93.95%, 92.17%, 86.12%, 79.12%, 74.74% and 83.51% respectively.2 Experiments in controlling cucumber powdery mildew indicated that polyoxin and Nongkang120 were good, Guweishi followed, Bailixiang oil was bad, Yinguo and matrine did not work. 14 days later after sprayed, the relative controlling effect of these 6 kind of bio-pesticides was 67.14%, 58.92%, 51.61%, 37.04%, 27.38% and 27.84% respectively.3 Experiments of using polyoxin, DT, kasugamycin, Zhiwudongli2003 and Nongyonglianmeisu to control cauliflower black rot indicated that all of them had effect. 5 days later after sprayed, the relative controlling effect was 80.93%, 76.21%, 66.64%, 66.64% and 38.07% respectively. Experiments of using kasugamycin, polyoxin, BailiXiang oil, Guweishi, matrine to control cabbage black rot indicated that all of them had not good effect.4 Experiments of using matrine4, Fuheliansu, Baicaol, Kupiten, Langdusu to control cucurbita pepo Aphid indicated that Fuheliansu had the best effect, 1 day, 4 days and 7 days later after sprayed, the relative controlling effect was 54.16%, 66.79%, and 69.41% respectively.Experiments of using Chongmanshuangke, Langdusu, Kupiten, lilac oil to control cabbage Aphid indicated that the chemical pesticide Chongmanshuangke had the best effect, 1 day, 4 days and 7 days later after sprayed, the relative controlling effect was 51.92%, 74.07%, and 77.61% respectively, the bio-pesticides Langdusu followed, 1 day, 4 days and 7 days later after sprayed, the relative controlling effect was 32.18%, 42.85%, and 46.79% respectively.Experiments of using matrine 1, Fuheliansu, Baicaol, Kupiten, Shengwushachongjil to control pepper Aphid indicated that matrinel had the best effect, 1 day, 4 days and 7 days later after sprayed, the relative controlling effect was 84.33%, 97.70%, 96.95% respectively.5 Experiments of using matrinel, Fuheliansu, Kupiten, Langdusu, lilac oil to control greenhouse whitefly in the green-house of eggplant indicated that matrinel and lilac oil had effect, 7 days later after sprayed, the relative controlling effect was 39.40% and 36.80% respectively.6 Experiments of using matrine3, Fuheliansu, Kupiten, Langdusu, lilac oil to control spider mite in the green-house of pepper indicated that Fuheliansu and Langdusu had effect, 7 days later after sprayed, the relative controlling effect was 78.08% and 76.08% respectively.7 Experiments of using Biruiling, Caierdi, Qiangdi312, Saifudin, Miechonglingl, Erwanqing to control cabbage tetranychus cinnarinus indicated that all of them had good effect, 7 days later after sprayed, the relative controlling effect of these 6 kind of bio-pesticides was 100.00%, 100.00%, 98.77%, 100.00%, 100.00%, 96.52% respectively. Experiments of using the same 6 kinds of bio-pesticides to control diamon-back moth indicated that Miechonglingl had the best effect, 7 days later after sprayed, the relative controlling effect was 94.67%.8 The contents of nitrate in 15 kind of main vegetables were tested. The results showed that the contents of nitrate was not the same in different categories and different kinds of vegetables. Also the contents of nitrate was different between lanzhou suburb and Yuzhong county. The nitrite contents in each tested vegetable was lower than the safe standard of 1 mg/Kg except the garlic in Lanzhou suburb and the radish in Yuzhong county.