Contents:
- Fungal diseases
- How to fight fungal diseases on hydrangeas?
- Hydrangea pests
Fungal diseases
Gray mold of hydrangeas- caused by the fungus Botrytis cinerea. The shoot tips are the first to die as a result of pathogen infection. Then the individual leaves turn black and the rot covers the entire stem. Individual flowers may turn brown.On the surfaces affected by the disease there is a gray, dense layer of mycelium.
Leaf spots of hydrangeas- most often affects the oak-leaved hydrangea. There are light, round spots with a darker border on the leaves. The spots enlarge to cover an increasing leaf surface, and then turn brown. As the infection develops, the leaves die and fall off. The disease develops in high humidity.
Powdery mildew- caused by the fungus Erysiphe polygoni. The spores of the fungus profusely cover the plant, which looks like it is sprinkled with flour. The first symptoms can be seen especially on the upper side of the leaf blade. Under favorable conditions, the disease spreads rapidly and infected tissues turn brown and die. Leaves and shoots affected by the disease grow slower and deform.
Root and base rot -caused by fungi of the genusFusarium., Pythium ultimum, is a disease affecting the climbing hydrangea. Immediately after planting, young plants wilt and die. You can see rot on the lower parts of the shoots, and the plant taken out of the soil has clearly browned and rotten roots. The plant, unable to absorb water and nutrients from the soil, turns yellow and withers. The disease affects both plants grown in soil and those in containers. The source of the disease can be diseased seeds, remains of infected plants or infected soil.
How to fight fungal diseases on hydrangeas?
As with any disease, prevention is the most important thing. The development of fungal diseases is favored by excessive plant density, over-fertilization or too abundant watering and sprinkling the leaves. Mushroom spores overwinter in infected plant debris, which should be raided and removed from the garden so that they would not be a source of infection.
It is worth strengthening the plants that will cope with the infection more easily. Strengthening and immunizing liquid manure, plant extracts and infusions, you can prepare yourself from commonly occurring plants.Stinging nettle manure and horsetail infusion have particularly valuable properties - they stimulate plant growth and make them resistant to fungal diseases.
When, despite all treatments, we observe disease symptoms on the hydrangea, nature itself comes to our rescue.
To combat powdery mildew on hydrangea, we spray it with horsetail decoction or nettle liquid manure. Spray plants and soil several times every 2-3 weeks until infection is cleared. Yarrow extract will help us in the fight against leaf spot, and garlic and onions against gray mold. If we do not have time or the ability to make our own preparations, we can reach for ready-made biopreparations based on horsetail, orange oil, grapefruit or garlic.
Hydrangea pests
Hydrangeas are resistant to attacks by most pests. Mainly aphids and spider mites can be observed there.
Aphids- can be seen mainly on the underside of leaves and on tops of shoots. Foraging insects suck the juices from plants, thus limiting their development and causing deformation of all organs. As a result, the plant dies completely.
A natural way to fight aphids is to spray them with potassium soap or baking soda. You can also spray with a natural preparation of wormwood, onion, garlic, nettle, yarrow, potato leaf or dandelion. In early spring, preventive measures can be sprayed with natural, oil preparations prepared independently or available for sale.
The spider mite- sucks the juice from the plant causing yellow discoloration on the surface of the leaves. They initially appear along the nerves in a mosaic pattern. With the development of the disease, discoloration covers the entire leaf blade. Heavily infested leaves turn yellow, turn brown, and eventually wilt and fall off.
The development of spider mites is favored by warm and dry weather, which is why we pay special attention to the presence of the pest during such conditions. When we notice the presence of a spider mite on a hydrangea, we can spray the entire plant with a decoction of tomato or potato leaves.In the fight against spider mite, the extract of white mustard seeds or the roots of field sorrel, which is sprayed several times at intervals of 7 days, will also be helpful.
As with the control of aphids, we can use preventive spraying with oil preparations and introduce the pear benefactor - a natural enemy of spider mites into the garden.
