Study On The Control Effects Of Four Biological Pesticides On Grape Powdery Mildew

Recently,the main grape cultivated in production are European grapes,which have the advantage of being of high quality and fragrance.However,the prominent disadvantage is the disability in disease resistance,especially in the resistance to powdery mildew.As a result,it often causes huge losses in agricultural production.At the current stage of grape production,chemical agents are commonly used to prevent the powdery mildew in China.Although the method of chemical control is effective,long-term application is likely to cause environmental pollution,endanger the health of humans and animals,and make germs resistant to drugs,which are not in line with green and healthy development.Breeding is another common and effective means of enhancing disease resistance.In recent years,some progress has been made in molecular breeding for disease resistance,it will still take a long time for agricultural production application,and traditional breeding techniques also need a long time.Therefore,the application of biological control is undoubtedly an efficient and environmentally friendly approach at present.In this experiment,four biopesticides with different ingredients were selected through preliminary research.Combining the experimental materials of potted plants and field plants,we compare the control effect of four biological pesticides.The main findings of the research are as follows.1.The grape powdery mildew races NAFU1 were inoculated to potted plants and the control plants,which were after applying pesticides,and cultivate them in a light incubator for3,5 and 10 days.Then,observed the growth status of the powdery mildew after staining by the Typan blue.The results showed that the length of mycelium treated with the four biopesticides respectively decreased by 506.23μm,480.00μm,494.63μm and 455.83μm compared to the control group;the number of spore peduncles on the control plants was 32and 84 after 5 and 10 d of inoculation,while the number of spore peduncles on the treated plants was less than 50%of the control group,indicating that the growth of powdery mildew mycelium on treated plants was suppressed in varying degrees.10 days after inoculation,the number of spore stalks in the treated group was still significantly different from the control group,while the efficacy of Physcion was lower than that of 5 days after inoculation,indicating that Physcion is not as persistent as the other three agents.The four biopesticides were ranked in order of effectiveness,with the conclusion that Artaling was the best,followed by Polyxins and Bacillus subtilis,and Physcion was relatively poor.all four biopesticides were significantly different from the control plants and showed significant control effects after application to the plants,which are naturally susceptible to the disease in the field.The number of spores obviously decreased after application and the most effective control was achieved around 3 days after application.After 7 days,the number of spores gradually increased,but it still had a suppressive effect compared to the control.Therefore,it is recommended to spray once a week during the periods of high powdery mildew incidence.2.Observed by DAB staining,we learned that the leaves treated with Artaling,Bacillus subtilis and Polyxins will all accumulate hydrogen peroxide compared to the control group.The accumulation of Artaling was the highest,reaching19.2%;Bacillus subtilis and Polyxins was 15.47%and 13.94%respectively;the accumulation of Physcion was the lowest with only5.83%,which is not different from the control plants.It indicates that the main function of Physcion may be sterilization,and it is less effective in improving the plant’s own resistance to disease.The CAT enzyme activity of the leaves of plants treated with Artaling was the highest among the four different groups of treatments,reaching 208.6 U/g,which was followed by Bacillus subtilis and Polyxins,and the lowest value of 101.7 U/g was obtained after treatment with Physcion.The effects of the first three agents were significantly different from the control,as well as the Physcion groups.This result is consistent with the accumulation data indicated by the hydrogen peroxide,and it can also prove that these three agents can improve crop disease resistance to some extent,with Artaling being the most effective.3.The photosynthetic characteristics of the plants treated with four chemicals were measured.The results showed that Physcion will affect the relative content of plant chlorophyll to some extent,while the other three agents will not.Four kinds of biopesticides can negatively affect intercellular CO₂ concentration and transpiration rate during photosynthesis in plants to some extent,but will not affect the net photosynthetic rate of leaves.In a word,the biopesticide has outstanding effects on the prevention and cure of grape powdery mildew’s green and safe.Chemical agents cannot achieve these advantages.The selection of bio-pesticides such as Artaling for the prevention and treatment of grape powdery mildew is in line with the development trend of green agriculture.