2020 Volume 86 Issue 1 Pages 9-16
Simeconazole granules were tested for suppression of white rot (Sclerotium cepivorum) of welsh onion (Allium fistulosum) in six trials in two experimental fields, including a naturally infested field, from 2010 to 2013. The influence of the method and timing of simeconazole application, field, and year as explanatory variables were analyzed using a generalized linear model (GLM). In our experimental model, the coefficient of simeconazole treatment applied once at the time of planting and the first earthing-up in reference to the negative control of simeconazole was −1.47. Analysis of deviance for the variable indicated that simeconazole treatment significantly suppressed the disease (p = 0.044). Although the coefficient of simeconazole treatment applied with first and third earthing-up in reference to the negative control was −1.10, the analysis of deviance showed that the variable was not significant (p = 0.255). There was no significant difference between the two simeconazole-application procedures (mixed into soil vs soil-surface dressing) in the GLM analysis done as mentioned above. When the influence of the origin and type of field infection on the results was considered, disease in the artificially and uniformly infested field was more severe than in the naturally and partially infested field. Although more trials are needed to adequately analyze the influence of year on disease outbreak, using the GLM analysis, we demonstrated that simeconazole is an effective suppressive treatment of white rot.
