| Walnut (Juglans regia) is one of the four nuts in the world, and also one of important species of woody oil grain in China.The walnut has rich nutrition value and high economy value. Hubei province is a major walnut production areas in China. Walnut cultivated area and the degree of culture centralization increased rapidly in recent years, but walnut disease increased year by year because of the lack of cultivation technology and management in orchard..In this paper, we isolated and identified the pathogen of walnut root rot in laboratory, and screening fungcides and formulation against pathogen of walnut root rot, and studied the technology of prevention and control walnut root rot. The results showed:1.Identifying the pathogen of walnut root rot in Baokang country: Applying the method of conventional organization separation, a Fusarium sp. was isolated from diseased root of walnut in Baokang country. Proved by Koch’s postulates, The pathogenicity experiment of strains separated were tested, the same Fusarium sp. strain Fl was separated from the plants inoculated again, strain F1 identified by morphology level and molecular biological level, strain F1 showed highest homology with landing sequence number of strains KJ019828.1 and KJ019827.1, and the homology had 99%, the minimum E-value.So the pathogen of walnut root rot was identified Fusarium solani in Baokang country.2.Screening fungicides against the pathogen of walnut root rot indoor: The toxicity of 19 fungicides and 8 fungicides formulaition on pathogens of walnut root rot, and co-toxicity between probenazole and prochloraz compound on pathogens of walnut root rot were determined by the mycelium growth rates method. The result showed that probenazole, prochloraz and carbendazim had higher toxicities among fungicides, the EC50 of 0.0926 mg/L,0.1078 mg/L and 0.7605 mg/L, respectively, with probenazole being the strongest. When probenazole and prochloraz mixing ratios were 1:3、1:5 and 1:7, the co-toxicity efficient (CTC) of 160.5345,182.8036 and 226.1941, respectively, the mixture of 1:7 was the most significant synergism.The prochloraz 40% EW and phenazino-1-carboxylic acid 1% SC had highest toxicities among all, with the EC50 of 0.2141 mg/L and 0.2304 mg/L, respectively.3.The hymexazol liquid formulation for trunk injection(HLF) processing:The HLF A(hymexazol 5% + oligosaccharins 2% + brassinolide 0.1%) and HLF B(hymexazol 5% + oligosaccharins 2% + 4-indolyl-butyric acid potassium 0.1%)were processing.2 HLF dilution stability, high temperature storage stability, room temperature storage stability, low temperature storage stability all were qualified.the pH were 4-5.the dumping test all were qualified.The toxicity of 2 HLF to pathogens of walnut root rot were determined by the mycelium growth rates method indoor. The results showed that 2 HLF had control efficacy to pathogens of walnut root rot after storage stability test. The EC50 of the HLF A and HLF B to pathogen were 351.0581mg/L、 370.1268mg/L、272.8126mg/L and 338.2527mg/L、362.1964mg/L、260.0417mg/L, respectively.The EC50 of the contrast fungicide hymexazol was 260.3889 mg/L.4.The trials prevention and control walnut root rot in the orchard:The result showed that, the treatment which injected 2 HLF in the base of walnut trunk was higher relatively control effect than irrigating fungicides under walnut roots. The relatively control effect on walnut root rot were 88.87% and 90.00%, respectively. The treatments of irrigation hymexazol 70% WP, lime sulphur, and phenazino-1-carboxylic acid 1% SC relatively control effect were 85.18%,83.33% and 81.66%, respectively. The treatment of azadirachtin composition microbial fertilizer control effect on walnut root rot was 77.77%.The pathogen of walnut root rot identified Fusarium solani in Baokang country, Hubei province. The relatively control effect of 7.1% HLF B and 7.1% HLF A on walnut root rot were highest in walnut garden, the relatively control effect were 90.00% and 88.87%, respectively. |
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