National Sunflower Association officials surveyed 70 fields in South and North Dakota over the past two weeks and found a lot of downy mildew. Association Director John Sandbakken says while the disease was present most of the sunflowers will be able to withstand it due to the new varieties that are resistant to it.
Sandbakken says the wetter conditions lead to more cases of downy mildew showing up. When it rains after planting, the pathogen produces spores that infect roots and cause a systematic infection.
Sandbakken says what’s positive is that the good rains have produced a healthy looking crop so far.
Those plants that get infected with downy mildew will often die and if they survive will not yield. The Association says yield loss doesn’t usually occur unless the disease spreads into large patches of a field.