Alternatives to Benomyl for Management of Cercospora Leaf Spot on Turnip Greens

in HortScience

Benomyl was compared with copper hydroxide, azoxystrobin, tebuconazole, acibenzolar-S-methyl, and basic copper sulfate for efficacy of cercospora leaf spot [incited by Cercospora brassicicola P. Henn] management on turnip greens [Brassica rapa L. var. (DC.) Metzg. utilis]. Treatments included various application times and were evaluated in three field experiments over 2 years. The few yield effects that occurred were not consistent between years. Copper hydroxide and basic copper sulfate were not useful alternatives to benomyl due to a combination of phytotoxicity symptoms and ineffective disease control. Inconsistent results were observed with acibenzolar-S-methyl. A single, early application of tebuconazole greatly reduced cercospora leaf spot severity relative to the control in both years. Tebuconazole may be a good alternative to benomyl if a label can be obtained. Multiple (at least two) applications of azoxystrobin may be needed to achieve the same degree of cercospora leaf spot control as would result from a single properly timed application of benomyl. Although azoxystrobin is now labeled for turnip greens, grower costs will likely increase as a result of benomyl being discontinued. Chemical names used: methyl-1-[(butylamino)carbonyl]-H-benzimidazol-2-ylcarbamate (benomyl); methyl (E)-2-{2-[6-(2-cyanophenoxy)pyrimidin-4-yloxy]phenyl}-3-methoxyacrylate (azoxystrobin); alpha-[2-(4-chlorophenyl)ethyl]-alpha-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (tebuconazole); 1,2,3-benzothiadiazole-7-thiocarboxylic acid-S-methyl-ester (acibenzolar-S-methyl).

If the inline PDF is not rendering correctly, you can download the PDF file here.

Contributor Notes

Professor, Dept. of Horticulture and Landscape Architecture, and corresponding author.

Article Information

Google Scholar

Related Content

Article Metrics

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 107 107 1
PDF Downloads 34 34 0