Mildew is an extremely annoying pest that affects numerous plants, to the chagrin of many gardeners. Cereal varieties are also often affected. An infestation here in particular 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.
How can you prevent and combat powdery mildew in grain?
Mildew in grain appears as white pustules, mealy coatings and dark spots on leaves. To prevent this, resistant varieties can be grown, mixed crops can be used and residues from the previous harvest can be removed. Sulfur-based fungicides and Corbel are approved for control purposes.
Symptoms
- small, white pustules on the leaves
- later a floury topping
- Dark brown spots appear when the grain reacts defensively
- small black fruiting bodies (especially on wheat)
When does mildew appear?
Young ears in particular are at risk of developing 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 precipitation
The fungus that causes powdery mildew overwinters in the mycelium of the grain and uses the cold season to reproduce. In spring it spreads to surrounding grain fields through the wind.
Prevention
- growing resistant varieties
- mixed cultures are best
- Carefully remove remains of the last harvest and loosen the soil well
- late sowing in autumn, early sowing in spring
- Do not grow summer crops in the main wind direction
- fertilize as little as possible with manure
Approved pesticides
Once an infestation has occurred, the affected ears must be treated as quickly as possible in order not to endanger neighboring crops. Two fungicides are currently approved for the control of powdery mildew:
- Sulfur-based agent
- Corbel
But before a farmer can resort to these remedies, a precise analysis of the intensity of the mildew infestation is necessary. For this purpose, 40 stalks are taken diagonally from the field and checked. The focus of interest are the three most recent sheets. If 30-60 leaves show noticeable symptoms, spraying the fungicide is justifiable.
