Studies On Environmental Quality Assessment Of Pesudostellariae Heterophylla (Mid) Product Base In Shibing And Prevention Techniques Of P.heterophylla (Mid) Leaf Spots Disease

Chinese Crude Drugs—Pesudostellariae heterophylla (Mid) is one of the commonly used drugs with its gentle characteristics. Shibing County of Guizhou Province is one of the main productive places. However, the leaf spots disease of P. heterophylla that has been greatly impacted its production and qualityis becoming more and more serious because of sole and large area cropping. Meanwhile, because farmers didn't use the pesticides reasonably, some products of P. heterophylla were checked pesticide residues exceed standard.To dealing with these problems, environmental quality of P. heterophylla planting field in Shibing County and the controlling technology of the leaf spot diease were studied. The results are as following:1. Used the single factor pollution indexes and the composite pollution indexes to estimate the environment quality of the base. The results showed that the rank of the atmosphere, water and soil's single factor pollution indexes are lower than 1.0, and the composite pollution indexes of the atmosphere are lower than 0.6, belonging to the frist degree; the water are lower than 1.0 belonging to the second degree; the soil are lower than 0.7, belonging to the third degree, they all comform to the standards of environment quality. Therefore, the environment condition of this area is completely suitable for planting the Chinese Crude Drugs—P. heterophylla.2. The study selected Fluazinam 50%SC, Amistar 25%SC and LC-l-c 30%ME to contrail the leaf spot diease.1) The toxicity test results show that the ED₅₀ order of the restraint to the leaf spot disease on P. heterophylla is: Fluazinam＜Amistar＜LC-1-c.2) The results in fields implies that Fluazinam diluted to 1000 times, Amistar diluted to 800 times and LC-1-c diluted to 600 times, have the best curity to the leaf spot disease. Field efficacy is75.1%,73.4%,75.3% respectively, and the increased income as 49.07ï¿¥,46.44ï¿¥and 35.84ï¿¥per 18 m² respectively. 3. Three groups were selected: Maize&P. heterophylla, Bean& P. heterophylla and Maize& Bean&P. heterophylla. Its control rates to leaf spots disease reached 75.0%,70.9%,73.9%, and they increased income as 37.15ï¿¥, 29.37ï¿¥and 33.96ï¿¥per 18 m² But Sunflower& P. heterophylla and Sunflower&Bean&P. heterophylla are the worst groups for increasing income, which are 4.06ï¿¥and 13.15ï¿¥per 18 m²3. The study has been made on the dynamic residue of Fluazinam 25%SC in the soil, the plant and stem of P. heterophylla, and the results are as follow:1) After increasing Fluazinam, the recovering rate is very high, 93.80 %～95.32 %, 95.29 %～97.83 %, 90.14 %～93.52 %are in the stem, plant of P. heterophylla and in the soil respectively. The variation coefficient is among 4.01%-7.05%, which meets the residue analysis standard.2) The residue degradation of Fluazinam 50%SC diluted to various times in the stem, plant and in the soil is accorded with first order kinetic equations. The highest residue in the roots and plants of P. heterophylla, and in the soil are 0. 1410mg/kg,0.0042 mg/kg,0.0957 mg/kg in a week after spraying. They were less than maximum residue limit (MRL) in America.3) The half-life of Fluazinam is very short. Its half-life on the roots, plants and the soil is 11-13 days, 8-9 days and 10-11days respectively. That means roots＞soil＞plants.4) A final detection of the residue of Fluazinam shows that there is no residue in the roots, plants and the soil.