Research On The Antifungal Spectrum Of Albendazole And Its Decrement And Synergism

Albendazole?5-propylthio-1H-benzimidazol-2-carbamate?,a compound of benzimidazole derivative,is a broad spectrum,low toxicity and systemic fungicide.In order to develop a sound recommendation for the use and exploitation of a new fungicide,the antifungal spectrum and the sensitivity of target creature should be studied.The toxicity of a new fungicide albendazole was studied against 13 species of important agricultural pathogens of different taxonomical position.The results showed that albendazole strongly inhibited mycelia growth of Rhizoctonia solani and Pyricularia grisea with EC₅₀ values of 0.1245 ?g/mL and 0.6111 ?g/mL,respectively.It also had high activity for Colletotrichum capsici,Colletotrichum glecosporioides and F.oxysporumwith EC₅₀ values of 2.2488?g/mL,1.3431 ?g/mL,1.1144?g/mL,respectively.The inhibition of B.graminis,F.moniliformeand,Alternaria solani was poor.But inhibition differences of sensitive and MBC-resistant strains of F.graminearum,Sclerotinia selerotiorum and Botrytis cinereawere great.This paper focuses on the inhibitory activity of albendazole to Rhizoctonia solani.The results showed that:the production of Rhizoctonia solani sclerotia decreased while concentration of albendazole increasing,but it had no effect on the germination of sclerotia;In vitro,a total of 113 isolates of R.solani were characterized for the baseline sensitivity to albendazole.The isolates werevery sensitive to albendazole and the baseline sensitivity curve was unimodal with an average EC₅₀ value of 0.1078 ± 0.0212 ?g mL^-1.The activity of the dual mixture of albendazole with other fungicide to control Rhizoctonia solani was evaluated by inhibiting mycelium growth on PDA medium.The results showed that the activity of different mixtures or different ratio of the same mixture were distinct.The mixures of albendazole,azoxystrobin and albendazole,pyrazole-kresoxim-methyl had excellent activity against Rhizoctonia solaniusing different ratio and ingredients,which can screen appropriate mixturesto reduce the resistance risk of Rhizoctonia solani to Jinggangmycin by alternating with Jinggangmycin in the field.In the field trial,control efficiency of albendazole at 300 g a.i./hm² 15 days after second application was 69.15%,much higher than the that of thiophanate-methyland Jinggangmycin which was42.55%and 53.19%,respectively.The control efficiency of albendazole and azoxystrobin was higher than albendazole,which efficiency at 300 g a.i./hm² is 77.66%.Therefore,albendazole had a certain value in the control of rice sheath blight,and was safe to the rice plants at the tested dosage.The activity of the dual mixture of albendazole with metconazole,metconazolewith chlorothalonil and metconazole with MBC against F.Graminearum was evaluated by inhibiting mycelium growth on PDA medium.The results showed that the mixture fungicide of albendazole with metconazolehad significant synergies againstcarbendazim-susceptible?MBC^S?strains and carbendazim-resistant?MBC^R?strains.Maximum efficiency coefficients were 2.1103 to MBC^S strains and maximum efficiency coefficients were 3.1204 to MBC^R strains.Metconazole with chlorothalonil also had significant synergies.The control effect of these dual mixtures against the wheat scab in the field was higher than that of control groups.In a word,the previous researches showed that albendazole and its dual mixture was effective against Sheath blight of rice and wheat scab.It might be a promising control agent.Further studies including mode of action,toxicity,formulation,and spraying methods will be useful for the commercialization and large-scale control against the diseases in the field.