The Screening Pesticides For Control Of Kiwifruit Bacterial Canker

Kiwifruit bacterial canker, which incited by Pseudomonas syingae pv. Actinidiae(PSA),is the most destructive disease in the production of kiwifruit and restricted the healthydevelopment of kiwifruit industry. With the enlargement of the cultivated area, the originalpesticides and prevention technology already couldn’t satisfy the production requirements.Therefore, the objectives of this study were to screen the effective pesticides from31commonly agents in the market by in vitro and in vivo trials. Meanwhile, in order to selectmore applied value of control agents to provide scientific guidance for agricultural production,the tentative experiment about complex pesticides were preliminary screened. The resultswere as follows:1. The screening result of pesticide products(1) Whether the pesticides had the antibacterial ability on PSA, the filter paper methodwas used to determine the virulence of31preparatory pesticides to PSA in vitro. The resultshowed that tetramycin, amobam, copper hydroxide, cuaminosulfate, resin acid copper salt,microbial agent, benziothiazolinone, EM bactericide and mancozeb were much more sensitiveto PSA and the EC50values is less than0.05mg/L; kasugamycin·copper oxychloride,chloroisobromine cyanuric acid, DT, thiram, metalaxyl·propamocarb, oxine-copper,zhongshengmycin, phenylate·jiahuan azole and saisentong were sensitive to PSA, with theEC50values between0.10and1.00mg/L; thiophanate-methyl, bismerthiazol, WCT extract,carbendazol,chlorothalonil and propamocarb bacteriostatic effect were relatively poor and theEC50were greater than1.00mg/L. Other7pesticides had no antibacterial ability to PSA invitro.(2) The nine sensitive kinds of pesticide products were chose to evaluate controlefficiency in pot experiment. Five pesticides were obtained in the finally. Among them, thetetramycin and benziothiazolinone had the best control effects, with the lowest diseaseincidence and the relative control effects were reached to84.76%and80.00%, respectively;the relative efficiency of copper hydroxide, EM bactericide and microbial agent between70%to80%; the control effect of resin acid copper salt and amobam were between60%and70%;control effect of cuaminosulfate copper and mancozeb were not ideal, the control effect werebelow60%. (3) The effective pesticides which screened in potted test were applied in the orchard toresearch the application method. The pesticide was tetramycin, benziothiazolinone, copperhydroxide, EM bactericide and microbial, respectively. The finally result showed that: thetetramycin and benziothiazolinone had the spruised effect after curettage of the lesion canker,the cure rate reached80%, and the recurrence rate of less than10%; copper hydroxide alsohad promising effect, with the cure rate was greater than70%, the recurrence rate of higherthan10%; microbial agent had the promising effect when used as spray prevention to cankerin kiwifruit, whose control effect was up to70%; the way of EM bactericide worked bestwhen used the methods of irrigating prevention and coated trunks prevention, the controleffect is greater than60%.2. Screening the synergistic complex pesticide(1) In order to screen more effective pesticide, the171complex pesticides, which wereobtained by the19kinds of pesticide matched each other, were preliminary screening by themethod of filter. We obtained61effective complex pesticides finally. There were18mixedagents with extremely sensitive to PSA, EC50was less than0.01mg/L,12kinds ofcombination were moderately sensitive to pathogen, with the EC50was between0.01and0.10mg/L,31kinds of combination were less sensitive, the EC50was greater than0.10mg/L.Wadley method was used to evaluate complex pesticides effects after the virulence wasmeasured. The results showed that there were18kinds of complex pesticides performancesynergistic effect among61effective combinations.13kinds of complex pesticides wereadditive effect,30kinds of complex pesticides were antagonistic effect.(2) The maximum coefficient of efficiency before five combinations were selected todetermined their control effect in pot experiment. Those five complex pesticides wasmancozeb+carbendazol, mancozeb+thiram, mancozeb+thiophanate-methyl, tetramycin+phenylate jiahuan azole, zhongshengmycin+carbendazol, respectively. The results showedthat the control effects of complex combination to kiwifruit bacterial canker were greater than60%. Among them, control effect of tetramycin+phenylate jiahuan azole reached86.81%,significantly higher than the effect of sole pesticide tetramycin (84.76%)andphenylate·jiahuan azole (40.00%); then was the mancozeb+thiram, with the control effect80.22%; both of the control effect for mancozeb+thiophanate-methyl and zhongshengmycin+carbendazol combinations were greater than70.00%; the less effective combinations wasmancozeb+carbendazol, but the control effect was still great than control effect when usedalone.3. The integrated control for the prevention and control of kiwifruit bacterial canker was formulated according to the result of pesticides screening and combined with the actualproduction. This technique provided service for agricultural production with the use of thegrowers.