Screening And Effect Evaluation Of Copper Bactericides For Control Of Citrus Canker Disease

Citrus is not only the largest fruit in the world,but also the largest fruit in my country,the vigorous development of the citrus industry is of great significance to the agricultural and rural economy.Citrus canker disease is one of the serious diseases affecting the development of citrus industry,it has the characteristics of wide spread,long harm time,difficult control and easy to be affected by temperature and rainfall.In production,chemical control is mainly used to inhibit the growth of Xcc,but the selection of the prevention and treatment of drug is relatively simple,and there is no systematic research on the specific control effects of commonly used drugs,at present,there are many phenomena such as excessive application times,unreasonable application time and application methods,etc.,in order to screen out effective control pesticides of citrus canker disease,reduce the number of application,grasp the critical period of prevention and control,put forward a more scientific control method,the toxicity of 16 kinds of copper bactericides for the control of citrus canker disease were determined in laboratory and the effects of copper bactericides on control of citrus canker disease were evaluated by spraying and root irrigation before inoculation,the differences in growth index,chlorophyll content and leaf copper content of sweet orange seedlings after root irrigation with an organic and an inorganic copper bactericides were compared,in order to provide a reference for scientific application of efficient prevention and control of citrus canker disease,the specific research results are as follows:1.The paper diffusion method was used to test the toxicity of 16 kinds of copper bactericides in the laboratory,it was found that there were significant differences in the ability of each copper bactericide to inhibit the growth of Xcc under the same concentration,and the concentration of copper bactericides were positively correlated with the inhibition rate,the higher the concentration of copper bactericides,the greater the inhibition rate.CB13,CB4,CB15,CB2 and CB5 had significant antibacterial effect,when the concentration of copper bactericides were 128 mg/m L,the diameter of antibacterial zone was 21.1 mm,14.7 mm,13.9 mm,12.9 mm and 12.8 mm,the inhibition rates were 71.6%,59.3%,56.8%,53.5%and 53.0%,respectively.2.In the pot experiment,a comparative test of the effects of 16 copper bactericides on the prevention and treatment of citrus canker disease by spraying and root irrigation before inoculating 10~4 cfu/m L Xcc,and 5 kinds of copper bactericides with better control effect were selected.The results showed that spraying diluted 500-fold CB2,spraying diluted 200-fold and diluted 400-fold CB3 could achieve better control effect on citrus canker disease,on the 14th days post inoculation(dpi),there were no ulcer spots on the leaves,and only a few spots on the leaves of plants with spraying diluted 750-fold CB2;The leaves of root irrigation with 4 m M CB11 and CB12 and 12 m M CB1 have only a few small disease spots,and the control effect is remarkable,at 8 dpi,the Xcc content per unit leaf area was 5.23cfu/cm~2,4.27 cfu/cm~2 and 5.55 cfu/cm~2,respectively,Xcc content per leaf area was significantly lower than that of other root irrigation treatments.3.There were significant differences in growth index,chlorophyll content and copper content in leaves of sweet orange seedlings after root irrigation of CB11(organic copper bactericide)and CB2(inorganic copper bactericide)with the same copper ion concentration for 7 days and 30 days.The results showed that root irrigation CB11 was more beneficial to the growth of sweet orange,could enhance the photosynthetic capacity of leaves,and had less copper residue in sweet orange after root irrigation,which could be used as the main pesticide to control citrus canker disease.