几种栽培措施对玉米纹枯病和小斑病的影响

摘要

栽培措施能直接或间接影响玉米病害的发生。本文研究播期、密度和施氮量等几种常见栽培措施对玉米纹枯病和小斑病发生的影响。通过2012－2013年连续在四川简阳的试验结果表明，供试的10个玉米品种中，春播和夏播玉米纹枯病的病情指数差异不显著，平均病情指数分别为23．42和23．54。但玉米小斑病的病情指数差异极显著，春播玉米和夏播玉米的平均病情指数分别为24．39和86．96。45000株／hm2和67500株／hm2两种密度的试验结果表明，密度增加会加重纹枯病和小斑病的发生，但差异不显著。对纹枯病而言，两种密度下都以目前生产上普遍采用的“1．0 m＋1．0 m”等行距栽植时病害发生最轻。对小斑病而言，常规密度45000株／hm2下，等行距栽植的病害要轻于宽窄行栽植的，高密栽培67500株／hm2下，等行距栽植的病害要重于宽窄行栽植的。在供试的6个施氮水平下，未见施氮量与玉米纹枯病和小斑病之间有明显的相关性。综上表明，选用合适的玉米品种，适时播种，合理密植可减轻病害的发生，有利于玉米高产稳产。%Cultivation measures have direct and indirect influence on the occurrence of corn diseases.In this pa-per,we have investigated effect of several cultivation measures on sheath blight and southern leaf blight of corn, including sowing date,planting density and application of nitrogen fertilizer.The field trials were performed from 2012 to 2013 in Jianyang,Sichuan Province.The results showed that there was no significant difference in disease index of sheath blight between spring sowing and summer sowing date among ten tested maize varieties,with the average disease indexes of 23.42 and 23.54,respectively.However,disease index of southern leaf blight had ex-tremely significant differences between the two sowing dates with the average disease index of 24.39 and 86.96, respectively.The experiment on the two different densities (45 000 plants/hm2 and 67 500 plants/hm2 )indicated that it could aggravate the occurrence of sheath blight and southern leaf blight when the planting density was in-creased,but their difference was not significant.As for corn sheath blight,the equal spacing “1.0 m+1.0 m”row,which was widely used in current cultivation,was the most appropriate because occurrence of the disease was the lightest.The occurrence of southern leaf blight was lower under equal row spacing than wide-narrow row spac-ing at conventional density (45 000 plant/hm2 ),but the disease index was higher under equal row space at high density (67 500 plant/hm2 ).There was no significant correlation between nitrogen application rate at six different levels and the two corn diseases.In conclusion,the suitable cultivation measures including disease-resistant varie-ties,optimal sowing date and rational planting density could reduce the occurrence of diseases so as to achieve high and stable yield of corn.