摘要
采用不同的方法对玉米弯孢霉叶斑病 (Curvlarialunata)的初侵染来源进行了初步研究。结果表明 :玉米种子内外均不带菌 ,不能作为病害的初侵染来源 ;病残体内的病菌能在地表越冬 ,作为翌年的初侵染来源 ;不同深度土壤中病残体上的病菌存活时间较短 ,不能越冬作为下翌年的初侵染来源。生长于PSA培养基上的病菌培养物在地表和不同深度的土壤中均能越冬 ,说明病菌的分生孢子可在不同环境下越冬 ,作为翌年的初侵染源。对 4种杀菌剂进行室内毒力测定的结果表明 :供试药剂中以 5 0 %福美双可湿性粉剂的EC50 值最小 ,为 1 1 .79mg kg,毒力最高 ,其毒力回归方程为y=3.33+ 1 .5 6x ,相关系数r为 0 .991 2 ,达极显著水平。其余供试药剂毒力大小依次为 :75 %百菌清可湿性粉剂 ,其毒力回归方程为y =3.78+ 1 .0 4x,相关系数r为0 .95 79,达极显著水平 ,EC50 值为 1 4 .89mg kg;75 %代森锌 ,其毒力回归方程为y=4 .0 1 + 0 .6 3x ,相关系数r为0 .95 5 5 ,达极显著水平 ,EC50 值为 4 4.5 7mg kg;75 %代森锰锌可湿性粉剂 ,其毒力回归方程为y =2 .0 8+1 .6 1x,相关系数r为 0 .96 70 ,达极显著水平 ,EC50 值为 6 4 .1 0mg kg。
The primary sources of infection of Curvlaria lunata were studied in several methods. The results showed that corn seed is not the primary source of the disease induced by fungi because fungi don′t exist in the interior of and on the surface of corn seed. But fungi in the residue of diseased plant on the surface of soil may become the primary source because they can live through the winter. Fungi in soil, despite the depth where they live, can′t be the primary source due to their short living period. When the isolates of fungi are cultured in PSA medium, its conidia can live though the winter, either on the surface or in soil. This showed that the conidia of fungi may become the primary source. The determination of the toxicity of four fungicides indicated that the most toxic is 50% thiram, with its value of EC 50 being lowest, 11.79 mg/kg. Its toxicity equation is y=3.33+1.56x and the coefficient of correlation is 0.991 2, significantly different at 1%. The other fungicides are sorted out in order as follows: 75% chlorothalonil, with its value of EC 50 being 14.89 mg/kg,its toxicity equation being y=3.78+1.04x and the coefficient of correlation being 0.957 9, significantly different at 1%; 75% zineb, with its value of EC 50 being 36.06 mg/kg, its toxicity equation being y=4.01+0.63x, and the coefficient of correlation being 0.955 5, significantly different at 1%; 75% mancozeb, with its value of EC 50 being 64.95 mg/kg, its toxicity equation being y=2.08+1.61x, and the coefficient of correlation being 0.967 0, significantly different at 1%.
出处
《吉林农业大学学报》
CAS
CSCD
北大核心
2002年第4期53-57,共5页
Journal of Jilin Agricultural University
