Analysis On Dominant Populations Of Two Important Pests And Diseases Of Maize And Its Control Research In Shanxi

Maize is the largest food crop in Shanxi.Due to the complex topography and diverse climate in Shanxi,the occurrence of maize pests and diseases is also serious.In particular,maize ear rot and maize leaf mites have been increasing year by year.Therefore,this paper studies the dominant populations and control methods of these two diseases and insect pests in Shanxi corn.The main research conclusions are as follows:1.Six fungi were isolated from corn ear rot in Shanxi,which were Fusarium,Aspergillus,Trichoderma,Mucor,Penicillium and Alternaria,and the average separation frequency of fungi from Fusarium was the highest,35.65%,and the average separation frequency of Alternaria was the lowest,0.52%.The frequency of fungal isolation of different genera in different regions was significantly different.Among them,the fungus of Fusarium was the highest in Shanxi,and it was the dominant population(genus)of corn ear rot.2.Four species of Fusarium were identified from the isolated isolates of Fusarium oxysporum,which were Fusarium oxysporum,Fusarium graminearum,Fusarium oxysporum and Fusarium oxysporum.Among the four species of Fusarium,except for the Datong area,the highest frequency of separation in Linfen,Lvliang,Jinzhong and Xinzhou areas is Fusarium oxysporum,which is the dominant species in these areas;the dominant species of Datong is Fusarium graminearum Kind.Moreover,there are significant differences in the frequency of separation of different species of Fusarium species in different regions.3.30% difenoconazole WP had the best effect on field control of corn ear rot;5% Nisoul 2000 times solution had the best control effect and long duration.4.The corn leaf mites in Shanxi mainly include T.serrata,C.sinensis and T.urticae.The species,quantity and dominant species of spider mites in different regions were significantly different.The dominant species in Datong and Yinzhou were truncated spider mites.The dominant species of spider mites in Lvliang and Jinzhong were Trunformis and T.urticae.The leaf mites of Linyi area are mainly cinnabar leafhoppers.5.The initial stage of the population of Shanxi leafhopper mainly refers to the middle and late June;it has entered the breeding period since mid-July;the middle and late August has entered the prosperous period;in early September,the leafhopper population began to enter its decline period.6.The vertical distribution of corn leafhopper on plants is generally the first to appear in the lower leaves of maize,but the number is very small.Before and after the end of July,there are some densities of leaf aphid in the upper,middle and lower parts of corn plants.At the peak of population reproduction,the leaves of the lower leaves were the most abundant,the middle part was the second,and the upper part was the least;in late August,the leaves of the middle leaves were the largest,the upper part was the second,and the lower part was the least.During the fading period,the average leaf sputum of the upper,middle and lower leaves decreased to varying degrees.7.When 3 or 4 leaves of the lower part of the corn plant were cut,the average amount of leaf sputum was significantly reduced,and the sputum inhibition effect was significantly better than that when only 1 piece or 2 leaves were cut off.Therefore,in the actual production,the method of cutting out the lower leaves of the corn plant and taking out the field destruction can be used to effectively reduce the damage of the spider mites.