Fusarium watch 2016
Fusarium was not as much of an issue in 2015 as it was in 2014 – for most farms at least. But, there were areas of the province where fusarium damage did show up.
The Canadian Grain Commission found that the northeast and east central regions still had a high number of samples with fusarium damaged kernels (FDK). The severity of FDK was highest in the south-east. Looking at either incidence of FDK or severity, almost all areas were noticeably lower than in 2014. Of course, individual fields may have been affected more severely.
The incidence of FDK is the percentage of samples that have at least some FDK, while the severity is based on the percentage FDK by weight.
Provincial surveys conducted in 2015 found fusarium head blight (FHB) in 34 per cent of common wheat and 44 per cent of durum wheat crops. The severity was 2.2 and 5.2 per cent respectively, which was higher than in 2014 and continues the upward trend observed in durum in past years. This survey measures fusarium infection, rather than fusarium damage. Fusarium infection can occur in the absence of fusarium damage, so even seed that appears sound could harbor fusarium species that may lead to seedling blight.
The seed testing labs track the incidence and severity of fusarium infection as well. In discussions with Discovery Seed Labs, Biovision Seed Labs and 2020 Seed Labs, the consensus is that incidence and severity of fusarium infection on seed is down considerably from 2014. However, the levels vary widely and are high enough to warrant seeking new seed (up to 10 per cent of samples) or using a seed treatment (up to 40 per cent of samples).
There is still time to get seed tested for the 2016 crop. Basic recommended tests include germination and thousand kernel weight to determine seeding rates, as well as screening the seed for diseases like fusarium.
Fusarium on the seed can lead to seedling blight, but generally does not cause FHB in the same year. FHB develops from infected residue. However, there is no evidence that burning or tillage are effective at reducing infection levels. This may be because neither effectively removes all the residue (including roots and crowns). It is not known what temperature is required to destroy the fungus.
Fusarium management is challenging because several strategies must be employed to be effective and even when all are done correctly, it can still cause damage. Fusarium management should include:
- Crop rotation (at least three crops, with as much diversity as possible);
- The use of the best genetic resistance available (see the 2016 SaskSeed Guide); and
- The use of fungicides (with optimum timing).
Fortunately, the Saskatchewan Wheat Development Commission initiated FHB risk maps in 2015 and will be making them available for spring and winter wheat growers again in 2016. The FHB risk map is a tool that helps producers to identify the level of risk of a FHB infection. The maps, in conjunction with a cost/benefit analysis tool help producers determine whether or not a spray application is worthwhile.
The FHB risk maps are based on the heading date for a specific crop. Producers should determine when the heading date is, then follow the maps as they are generated for that heading date. Another tool on the Sask Wheat website helps to determine how fast heading will come on and identifies the optimum spray timing.
Fusarium is a pathogen that requires a lot of planning for. It affects planting decisions and seeding management and requires integrated pest management throughout the growing season. Knowledge is the key to reducing fusarium – knowledge about the quality of seed going in the ground, crop rotation benefits, the value of genetic resistance and how to make the most of a fungicide application. The resources available in association with Sask Wheat’s FHB risk maps are a good source of knowledge.
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