Study On Corn Stalk Rot In Henan Province

At the peak period of the occurrence of corn stalk rot in2011and2012, the main cornplanting areas of Henan province cause great loss. Diseased samples were collected from42counties of14cities in Henan Province. Pathogen isolation and identification conducted onPDA and CMA medium resulted proved that the main pathogens of corn stalk rot in Henanwere Fusarium. The separation frequency of Fusarium was higher and the distribution rangeof Fusarium was so wide that it could be isolated in every sampled region; the separationfrequency of Pythium was narrow and could only be isolated from some diseased plantscollected from Luohe Academy of Agricultural Sciences and Nanyang.163monosporousstrains of Fusarium were Isolated. The strains of Fusarium were identified morphologically atfirst, and then species-specific primers were used for the PCR detection on this basis;Translation elongation factor1-α (TEF-1α) and BLAST were then applied to sequence andanalyze the part of gene fragment of the strains that could not be identified by PCR. The163strains were finally identified to species. The results shows that F. graminearum are thedominant species among the163strains, accounting for44.2%(72), followed by F.proliferatum and F. verticillioides accounting for28.8%(47) and27.0%(44), respectively.The F. verticillioides was the dominant species of Jiaozuo, Luoyang in northwest of Henan,and Xuchang in the middle of Henan, which accounted for47.6%,50.0%and45.5%,respectively. F. proliferatum was mainly isolated from Shangqiu and Kaifeng in east of Henan,accounting for42.9%and57.1%separately. F. graminearum was the main species fromAnyang (66.7%), Puyang (71.4%) and Xinxiang (62.5%) in northern Henan; Nanyang (57.1%)and Zhumadian(45%) in the southern Henan,; and Zhengzhou (57.1%) and Luohe (66.7%) inthe central Henan. Pathogenicity test of indoor potted plants and field inoculation experimentsclearly showed that the pathogenicity of F. graminearum was the strongest. In the laboratory,Fungicides, Carbendazim and Difenoconazole azole, were used to test the sensitivity of thecollected strains, indicating that the inhibition rate of Difenoconazole azole to F.graminearum is higher. The strain S19-1(laboratory number) was used as pathogen in fieldtest for fungicides screening and variety resistance identification with toothpick inoculationmethod.This study clarified that corn stalk rot in Henan was caused by a complex of Fusarium. The pathogenicity of F. graminearum was the strongest among the various isolatedpathogens. In the aspect of pharmacy sensitivity, the inhibition rate of Difenoconazole azolewas higher than that of Carbendazim. In terms of variety resistance, Zheng958andXianyu335possessed a stronger resistance to stalk rot, while Luoyu818and Xundan20owna stronger susceptivity to stalk rot in the field test of Luohe and Yuanyang. In the aspect offield fungicides screening, the control effect of Triazole was better than other agents. Thissduty could provided as a reference for corn stalk rot control in Henan Province.