Relationship And Control Of Fusarium Stalk Rot, Ear Rot And Seedling Root Rot In Maize

Stalk rot,ear rot and seedling root rot diseases which were the major diseases on maize have occurred seriously in recent years. These three kinds of diseases which were caused by either various pathogeny singleness or complex used to be studied separately.In this paper, samples of stalk rot.ear rot and seedling root rot from Hebei province were collected, isolated and characterized through five years. The results showed that the main pathogens of stalk rot,ear rot and seedling root rot were Fusarium moniliforme and F.graminearum ?Further isolation ofFitsarium spp in different node and development stages was conducted after inoculated Fusarium spp (which refers to Fusarium moniliforme and F.graminearum, the same below) . It was illustrated the following infection mechanism: Fusarium spp cause stalk rot through walking to the next of stalk in the plant after seedling root rot occured. It then reached the ear along the stalk over a relatively long period and reached ear by harvest season. Therefore, Fusarium spp which caused ear rot were actually infected from outside the plant.The pathogenic ity of Fusarium moniliforme and F.graminearum on different parts of the plant were examined. The results illustrated that there were significant differences between the pathogenicity of isolate 3 , isolate 8 and other species . Thus there were specializations of Fusarium moniliforme and F.graminearion which infected different part of corn causing stalk rot.ear rot and seedling root rot.The following conclusions can be made through the comparison of the incidence of disease or the disease severity at different growth stages of inoculated Fusarium spp stalk rot,ear rot and seedling root rot. The highest average incidence of disease of inoculated stalk rot during seedling date was 65.7%; The second highest average incidence of disease of inoculated stalk rot during pollination was 56.7%; The lowest56average incidence of disease of inoculated stalk rot during the full-grown stage was 11.3%. The best inoculative period for seedling root rot was also seedling date, during which the the disease severity was 57.7%o The best inoculative period for ear rot was milky rape with the disease severity 72.7%= Rape stage was the least infected period with the disease severity 6.7%.Activities of the three defense enzymes: PPO,PO and PAL in plants were determined after inoculated seedling root rot . It was found that the trends of PPCK PCK PAL of different corn varieties with different resistance to seedling root rot disease were different after inoculated with seedling root rot disease funfi. The activities of the PPO of the susceptible varieties were lower than that of the CK at 12 hours alter inoculated. The activities of the PPO of the high resistant varieties were increased within 24 hours, while at the same time the activities of the PPO of the susceptible varieties were decreased. The activities of the PO of the high resistance varieties experience an elevated process within 24 hours after infected. On the other hand, the activities of the PO of the susceptible varieties were declined. However, there was no obvious trend for the activities of the PAL of both the resistant varieties and the susceptible varieties. Therefore, the early stage the resistant varieties against seedling root rot could be predicted by studying the trend of activities of the PPO> PO in the plant after inoculated.Diniconazole was determined to be a effective chemical after chemical screening indoor. It had a control effect of 83.42% against seedling root rot and could help to reduce the incidence of disease of stalk rot by 28.0%. The results of fertilizer experiments showed that the incidence of disease of stalk rot can be increased by 41.0% through straw returned field and potash fertilizer and manure have significant control effect against corn stalk rot with incidence of disease 24.9% and 24.5% lower than that of the ck respectively. The corn hybrids of high resistance to corn stalk rot were NongdalOS and JifengSS. The corn hybrids of high...