What causes powdery mildew?

What causes the fungal disease often

The disease is caused by a whole range of tube and egg fungi; there is no special mildew fungus. The bacteria survive as spores in the soil and partly as mycelium in buds and shoot tips.

The fungus emerges from these organs in favorable weather conditions, provided that it finds food through plant tissue. The exact cause of the infestation varies. Ascent mushrooms grow best in warm and dry weather, while egg mushrooms do well in damp weather.

The first signs are often thin, cobweb-like braids. Later the plants become ailing and a white coating is created that is reminiscent of flour. Therefore the name mildew.

Signs of the fungal attack:

• There are cobweb-like braids at the shoot tips.
• Plants ailing.
• A white coating appears on leaves, buds and fruits.

Differentiate between powdery mildew and downy mildew

The pathogen that causes the disease is different. Ashes cause powdery mildew, egg fungi are the cause of downy mildew.

Ascent fungi survive as spores or mycelium on the plants. They multiply in warm weather, especially when it's humid. At the beginning only the delicate network can be seen, later the fungus spreads on the upper side of the leaf. The leaves dry up and die.

Egg fungi, which cause downy mildew, overwinter in the soil. They attack the plants in damp weather and penetrate deep into the leaves. Brown or gray spots can be seen on the top. The floury topping can be found on the underside of the leaf. If the infestation is severe, the leaves die off.

Preventive measures against powdery mildew

Plant resistant varieties of plants. Breeders have many in the past Roses and vegetables grown that the mushrooms cannot harm.

Strengthen the immune system by injecting horsetail extract. Fertilize with little nitrogen. The nutrient allows the plants to grow quickly, which causes leaves to form with loose tissue. The mushrooms can nestle easily.

It is very important not to put the plants too close together. Make a cut for loose growth. The wind should dry the leaves quickly so that downy mildew has no chance.

Little is known about the fact that some species of ladybirds kill the mushrooms. The larvae and the adult beetles of the species sixteen-spotted Ladybug (Halyzia sedecimguttata) and twenty-two-spot ladybirds (Psyllobora vigintiduopunctata) graze on the fungal lawn. You can get both Beetles from specialist dealers.

A mixture of one part fresh milk and nine parts water has proven itself. The microorganisms in milk destroy the fungus, the lecithin it contains strengthens the plants. Inject with the agent two to three times a week for control and prevention.

Overview of measures

The table provides useful tips on how to prevent the disease from spreading.

Fight and prevent powdery mildew

method	Note
choose resistant varieties	is the safest way to prevent a new outbreak after a severe infestation
Maintain planting distances	prevents transmission between plants Leaves dry faster
Disinfect tools with alcohol	prevents transmission between plants
Inject plant tonic	strengthens the natural defenses of plants
Use nitrogen fertilizers sparingly	prevents large leaves with loose tissue
splash with fresh milk	Microorganisms fight the fungi
Insert ladybugs	sixteen-spotted ladybirds (Halyzia sedecimguttata) and twenty-two-spotted ladybirds (Psyllobora vigintiduopunctata) feed on powdery mildew fungi

As a rule, what exactly causes powdery mildew is not that important. The preventive measures and the control of the plant disease are more important.