Formula Selection And Field Efficacy Trials Of Pyraclostrobin And Ethylicin On Cucumber Downy Mildew

Downy mildew is a kind of serious diseases in Cucumber plants.It favors weather of low temperature and high humidity,under which it quickly develops and spreads widely,especially in green houses,and results in server loss of production of cucumber.In this paper,we set different rations of agents and applied them to potted cucumber plants infected by downy mildew pathogens.The bio-activity of downy mildew pathogens was then detected to determine the optimum proportion of pyraclostrobin and ethylicin.They were then applied to cucumber plants in field to a limited extent to ensure that 40%pyraclostrobin plus ethylicin EC had no adverse effect on plant growth.Finally,40%pyraclostrobin plus ethylicin EC was applied to cucumber plants to conduct a field trial,the results of which would be beneficial for the future application in production.All the results were summarized as follows:1.The results of bioassay experiment with potted plants showed that The inhibited occurrence of pyraclostrobin TC on cucumber downy mildew must be higher than ethylicin TC.The EC₅₀ of pyraclostrobin TC was 16.56 g/m L,and EC₅₀ of ethylicin TC was 79.32?g/m L.Among 5 different combinations of pyraclostrobin TC and ethylicin TC,EC₅₀ was minimum in ration 20+20,it was 16.80?g/m L.And the synergistic coefficient SR value was maximum,it was 1.63.The other four different combinations also have different degrees of additive effect.2.20%Pyraclostrobin TC and 20%ethylicin TC were processed into new agents.The formulation was as follows:20%pyrazolyl ether ester,20%allicin,15%cyclohexanone,10%pesticide emulsifier 602?styrene phenol polyoxyethylene ether?,4%pesticide emulsifier 500?calcium twelve alkylbenzene sulfonate?,3%fast permeable agent T?two isoxaline of maleic acid?Ester sulfonate)and 28%solvent 150?light aromatic hydrocarbon solvent naphtha?supplement.The quality test results showed that the suspending agent of 40%matrine and pyrazolactone SC was qualified,as all the tested index were up to standard.3.Field trial results show that:?1?40%matrine and pyrazolactone EC 30¹20 g/mu had no effects on the growth of cucumber plants.?2?40%matrine and pyrazolactone EC20³0 g/mu?120 g/ha¹80 g/hectare for effective components?showed positive inhibition on downy mildew in the field.In the field of Yangling,the occurrence of pathogen decreased 64%-75%on Day 7 after spraying,and 61%-73%on Day 14 after spraying.In the field of Qishan,the occurrence of pathogen decreased 60%-72%on Day 7 after spraying,and57%-69%on Day 14 after spraying.4.This study showed that 40%pyrazolone acetate and Allicin milk oil had a certain control effect on cucumber downy mildew.The suitable dosage was 20³0 g/mu?120 g/ha¹80 g/hectare for effective components?in field application.It was sprayed when the cucumber downy mildew started to show the disease spot.The leaves and stems of the plants were sprayed evenly and sprayed at intervals of 7¹0 days.Continuous spraying 2³ times.