Powdery mildew is an extremely annoying pest that afflicts numerous plants, much to the chagrin of many gardeners. Cereal varieties are also often affected. Here in particular, an infestation has significant consequences for the economy. However, if the symptoms are recognized in time, you can take action against the plant pest with the right knowledge.
Powdery mildew does not stop at grain either
symptoms
- small, white pustules on the leaves
- later a mealy topping
- when the grain reacts, dark brown spots appear
- small black fruit bodies (especially on wheat)
When does powdery mildew appear?
Young ears in particular are at risk of contracting powdery mildew. Triggers that favor the fungus are
- either very high or very low humidity
- little sunlight
- Temperatures in the range of 12-20°C
- Damage and injuries to the leaves
- mild, dry spring and autumn months
- generally little rainfall
The fungus that causes powdery mildew overwinters in the mycelium of the grain and takes advantage of the cold season to reproduce. In the spring, it spreads to the surrounding grain fields with the wind.
Prevent
- grow resistant varieties
- mixed cultures are best
- Carefully remove the remains of the last harvest and loosen the soil well
- late sowing in autumn, early sowing in spring
- Do not plant summer grain in the prevailing wind direction
- fertilize with liquid manure as little as possible
Approved plant protection products
Once an infestation has occurred, the affected ears must be treated as quickly as possible in order not to endanger neighboring stands. Two fungicides are currently approved for controlling powdery mildew:
- Sulfur based agent
- Corbel
But before a farmer can resort to these means, a precise analysis of the intensity of the mildew infestation is necessary. For this purpose, 40 stalks taken diagonally from the field are checked. The three most recent sheets are the focus of interest. If 30-60 leaves show noticeable symptoms, spraying the fungicide is justifiable.