COMPOSITION OF A POPULATION OF VENTURIA-INAEQUALIS RESISTANT TO MYCLOBUTANIL

被引：43

作者：

BRAUN, PG

MCRAE, KB

机构：

[1] Research Station, Agriculture Canada, Kentville, NS

来源：

CANADIAN JOURNAL OF PLANT PATHOLOGY-REVUE CANADIENNE DE PHYTOPATHOLOGIE | 1992年 / 14卷 / 03期

关键词：

D O I：

10.1080/07060669209500878

中图分类号：

Q94 [植物学];

学科分类号：

071001 ;

摘要：

Two techniques for determining the sensitivity of populations of Venturia inaequalis to sterol-demethylation inhibiting fungicides (DMIs) were compared for efficiency, correlation, and precision. Monoconidial isolates collected from orchards treated or not treated with DMIs were assayed by a modified mycelial suspension (MMS) technique and an agar plug (AP) assay. The MMS assay gave 25% lower mean population ED50 values than the AP assay. The two assays were highly correlated and were of similar precision. Both assays described two distinct populations of V. inaequalis, one sensitive and the other resistant to myclobutanil. The MMS assay used one-third less medium and required one-half the time of the AP assay with a potential to further reduce the time required to complete the assay. A wild-type population of V. inaequalis showed a unimodal, lognormal distribution of sensitivities to DMIs, with a mean ED50 of 0.055 mug/mL and a range from 0.005 to 0.2 mug/mL of myclobutanil. A population of V. inaequalis that had been exposed to various DMIs over 12 years showed a bimodal, lognormal distribution of sensitivity to DMIs, with mean ED50 values of 0.045 and 0.46 mug/mL for the sensitive and resistant populations, respectively, a range from 0.012 to 1.6 mug/mL, and a resistance factor of 10.2 (mean ED50 of resistant population/mean ED50 of sensitive population) for myclobutanil. Both assay methods showed that the mean log10 ED50 values for the sensitive and resistant populations within the sample differed by a factor of ten. These data are consistent with the quantitative changes in resistance to DMI fungicides reported for other pathogens.

引用

页码：215 / 220

页数：6

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