Analysis On Epidemic Factors Of Fusarium Head Blight In Rice-wheat Rotation Area

Fusarium head blight(FHB)is one of the important diseases that restrict wheat production in China.Due to climate change and farming reform,FHB in China has been aggravating year by year.An expansion trend from north to west not only resulted in a serious reduction of wheat production,but also the toxins in diseased grains seriously threaten human/animal health and food security.The prevalence of FHB is affected by multiple factors,and it is of great significance to find the main factors affecting the prevalence of FHB.In this thesis,the dynamic monitoring of Fusarium asiaticum spores,field simulation experiments,meteorological factor collection and disease investigation were conducted to analyze the main factors affecting the prevalence of FHB in rice-wheat rotation area of Jiangsu Province.We obtained the following main results:1.The association relationship between the dynamic changes of Fusarium asiaticum spores in the air of rice-wheat rotation areas and the incidence of FHB were preliminarily determined.By spore trapping,q PCR,field disease investigation and correlation analysis,two wheat growth periods including sowing stage and filling stage of wheat showed large amounts of Fusarium asiaticum spores in Jiangyan(central Jiangsu)and Zhangjiagang(southern Jiangsu),sowing stage of wheat showed large amounts of Fusarium asiaticum spores in Hongze(northern Jiangsu);The results of spore trapping showed that the average amount of spores in 40 cm was the most,followed by 70 cm and 100 cm.However,there was no significant correlation between the number of Fusarium asiaticum spores and the incidence of FHB.2.The relationship between the number of perithecium-generating rice stump and the incidence of FHB was studied.Field simulation experiments were carried out in northern Jiangsu,central Jiangsu and southern Jiangsu.The treatments of different rice stump density were arranged according to random groups.The perithecium-generating rice stump rate and incidence of FHB were investigated at wheat heading stage and dough stage.From 2021 to2023,perithecium-generating rice stump rate was southern Jiangsu>central Jiangsu>northern Jiangsu.The incidence of FHB was southern Jiangsu>central Jiangsu>northern Jiangsu in2021 and 2022,and northern Jiangsu>southern Jiangsu>central Jiangsu in 2023.The effect of the number of perithecium-generating rice stump on the incidence of FHB was different in different years.There was no significant correlation between the number of peritheciumgenerating rice stump and the incidence of FHB in northern,central and southern Jiangsu in2021 and 2023,however,there was a very significant correlation in northern and southern Jiangsu in2022.3.The relationship between meteorological factors and the incidence of FHB was preliminarily clarified.Based on the monitoring of meteorological factors and the investigation of the degree of disease,it was found that the main meteorological factors affecting the prevalence of FHB in rice-wheat rotation area were total rainfall in the early and mid-February,total rainfall from late March to early April,average dew point temperature in the mid and late April and average relative humidity from late April to early May.