Pycnidiospores of Leptosphaeria maculans as primary inoculum and their infection on canola at different growth stages to develop a predictive model
Leptosphaeria maculans causes blackleg disease ofcanola (Brassica napus L.). Canola plants at cotyledon, 3-leaf and 6-leaf stages were placed for one week in a blackleg-infested canola field during the summers of 2004 and 2005. The plants were then returned to the greenhouse and grown to maturity to rate disease severity (DS) on infected plants. Very high numbers of pycnidiospores were trapped on spore traps each week. Examination of stubble also showed that pycnidia were the predominant spore-beating structures. Two-year old blackleg-infected stubble buried in mesh bags and re-isolated from field also showed a significantly higher number of pycnidia being formed on stubble. Results confirmed that pycnidiospores can be considered as primary inoculum. There were no significant differences in DS at different growth stages. The results indicated that the disease severity can be modeled for plants infected at three different stages with regard to pycnidiospores as primary inoculum and epidemiologically important environmental factors. Among environmental factors only rainfall was strongly associated with DS.The model to predict the DS (Y) of plants infected at cotyledon stage was based on total rainfall (X) per week was Y=-0.004X2 +0.2X +1.45 (R2=0.63). The models for plants infected at 3-1eaf and 6- leaf stages were Y-=-0.003X2 + 0.15X + 1.13 (R2=0.79) and Y=-0.0014X2 +0. 1X + 0.69 (R2=0. 55) respectively. There was a linear relationship between pycnidiospores concentration (m3/h)and total rainfall received per week.
canola blackleg Leptosphaeria maculans modeling pycnidiospores growth stage
Kaveh Ghanbarnia W.G.Dilantha Fernando
Department of Plant Science, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
国际会议
第十二届国际油菜大会( The 12th International Rapeseed Congress)
武汉
英文
1362-1365
2007-03-26（万方平台首次上网日期，不代表论文的发表时间）