Preliminary Studies On Control Effects Of Three Fungicides To Corn Top Rot

In recent years, the corn top rot caused by Fusariurn subglutinans is a new disease onmaize production in China. At present, there are seldom domestic researches and systemresearch reports or effective measures against the disease. Through the indoor toxicityexperiment, screened the effeccient fungicides which can inhibit the growth of Fusariurnsubglutinans, analyzed the different toxins filtrate effects on corn radicle and germ growth,further defined the initial site where Fusariurn subglutinans effccts the parastisu, lay thefoundation for preliminary proved the the pathogenic mechanism usariurn subglutinans on themaize plants. At the same time, further cleared the effect of the corn top rot on photosythesischaracter, chlorophyll content, root activity and protective enzymes through field tests,providing theoretical basis for quick survey of the disease forcast of yield loss and scientificprevention.1. The growth rate method was used to determine the inhibition effect of7fungicides onFusariurn subglutinans was measured. The results showed that the EC50of fludioxonil wasthe smallest. The sensitivity of pathogen to this fungicide was the highest, and its inhibitoryeffect was best. The EC50of tebuconazole and carbendazim were smaller, the sensitivity ofpathogen to them was higher, and their inhibitory effect was better.2. The control effect of25g/L fludioxonil FS,60g/L tebuconazole FS and80%carbendazim WP corn top rot was measured though corn seedlings experiment in greenhouse.The results showed that corn seeds’ by the medicament treated which germination rateshowed a significant increase. Corn seeds which by the25g/L fludioxonil FS treated,its’germination rate was the highest and the control effect was best. Its’ germination rate andthe control effect by the60g/L tebuconazole FS treated were smaller and the control effect of80%carbendazim WP were worst. The greenhouse seed coating suggested that the25g/Lfludioxonil FS and60g/L tebuconazole FS could be applied in the control of the corn top rot.3. At the same time, the indoor toxicity experiment research has further defined thepathogenic mechanism of Fusariurn subglutinans to maize seedings. The results showed thattoxins produced by the Fusariurn subglutinans on corn radical growth had more obviousinhibitory effect than on corn germ growth. The phenomenon reflected the initial position where toxins came into play was the parastism’ root. Corn seeds which by the25g/Lfludioxonil FS treated, to join different concentrations of toxin filtrates, the growth of radicleand embryo were best and the control effect against Fusariurn subglutinan was highest. Its’the growth of radicle and embryo and the control effect by the60g/L tebuconazole FS treatedwere smaller and the control effect of80%carbendazim WP were worst.4. Field trials of quantitative artificial inoculation about2years were conducted toascertain the effects of photosythesis character, chlorophyll content, root activity, protectiveenzymes activities and yield of summer maize at seedling stage, big bell mouth stage, fillingstage and ripening stage. The results showed that the photosynthetic characteristics andchlorophyll content and root activity of the corn top rot were influenced certainly, and theSOD, POD and CAT activity of which were reduced significantly. The results showed that,with concentrations increasing between different treatment of fludioxonil, tebuconazole andcarbendazim, strengthen the corn protection, improve the control effect, promoting the effectof yield increase compared with the control.