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Wheat Fungicide Seed Treatment - Field and Greenhouse Research Update (05/10/18)

There are a few key factors that will influence the decision to use a fungicide seed treatment in wheat.

Wheat Fungicide Seed Treatment - Field and Greenhouse Research Update

There are a few key factors that will influence the decision to use a fungicide seed treatment in wheat. These include the seed source being used, field conditions, field history of root rots and seedling blights, and production practices. A general agreement among plant pathologists in the United States indicate a fungicide seed treatment in wheat is most effective on seed borne diseases (i.e.: loose smut; Figure 1) and the residual of the fungicide should not be viewed as having season long protection. A more detailed narrative of these topics has been outlined in a joint Extension publication from the University of Minnesota and North Dakota State University. The primary focus of this article is to provide an update on the stand response of a fungicide seed treatment and the effect of a fungicide seed treatment on a scabby seed lot.

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Wheat Field Trials – Fungicide Seed Treatments

A few years ago I wrote an article summarizing data from fungicide seed treatment trials conducted at several locations in North Dakota from 2003-2014. I have since updated this data set and have included results from 2015-2017. The updated data set now represents stand count data for 220 replicated fungicide seed treatments from 43 trials (Figure 2).

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A mean stand response of 7.2% was observed across the trials and 73% of the fungicide seed treatments resulted in a positive stand response (greater than zero). This data set provides a snapshot on the variability observed with a fungicide seed treatment. One area that this data set does not address is variability observed in different regions of North Dakota. With that in mind, Ryan Buetow (portion of Ph.D. research) is managing field trials in western (Hettinger and Dickinson) and eastern North Dakota (Fargo and Grand Forks) to evaluate the performance of fungicide seed treatments with regards to tillage practice, previous crop and soil conditions.

Scabby Seed Lot Greenhouse Trials

The scab epidemic of 2016 resulted in questions of using Fusarium infected seed (scabby seed) as a seed source in 2017. If a scabby seed source is to be used, it is recommended to clean the seed, use a fungicide, check the germination rate, and adjust plant populations accordingly. Several questions were posed on what type of fungicide is most effective. As a way to help address some of these questions, greenhouse trials were conducted by an undergraduate research assistant (Connor Rieniets) that evaluated the effect of fungicides on the germination rate of scabby seed. The durum seed source used for this trial had a germination percentage of 47%, a deoxynivalenol (DON/VOM) level of 9.3 ppm and 15 out of every 100 kernels was infected with Fusarium. Four single fungicide seed treatments differing in mode of action were used for the trial (Figure 3). Results indicated that germination improved when fluxapyroxad (SDHI), pyraclostrobin (strobilurin) or triticonazole (triazole) was used on the scabby seed source. Metalaxyl is a fungicide that has good efficacy on Pythium, but has little to no activity on Fusarium.

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Andrew Friskop

Extension Plant Pathology, Cereal Crops

This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

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