Recognize and treat hedge diseasesWith hedge diseases, targeted action is required. This guide shows how to nurse your plants back to health.
– Diagnosis of hedge diseases – Preventing hedge diseases – Causes of hedge diseases – Detecting and controlling fungal infections in hedges – Detecting and controlling pests in hedges – Diseases specific to hedges – Summary
Correct diagnosis of hedge diseases
Healthy, dense hedges are a garden owner's dream. But like many other plants, hedge plants are not safe from fungal and pest attack. If discoloration, bald spots or holes occur, you should be able to identify the cause in good time, eliminate it and treat possible diseases. In this summary we will talk about the typical diseases of hedges and how to fight them.
How to prevent hedge diseases
Work only with clean garden tools. Otherwise, fungal spores and dirt can get onto the sensitive, freshly cut shoots of the plants. Our guide shows the best way to clean your hedge trimmer.
Do not throw the infested plant parts on the compost heap. Here's how to avoid further spread of the fungi. Pests in your garden. Whether diseased plant parts are disposed of in the organic waste garbage can or as residual waste varies from place to place. Inform yourself about this in your municipality.
To keep the hedge permanently fit and vital, plant only hedge plants suitable for the site and ensure healthy growth with regular pruning and fertilizing.
Moisture favors the spread of fungi and pests. Stick to the recommended spacing when planting. Keep the hedge opaque. Becomes better aerated. With denser planting, plants will interfere with each other. Water mostly at the roots to keep shoots and leaves dry.
Fertilize the hedges sufficiently, but not too much. Use organic fertilizers in the spring. Potassium-containing nettle or horsetail decoction in late summer. To strengthen the tie of the plants. Provide them with sufficient potassium.
The You can prevent hedge diseases already at the time of purchase, by choosing high quality plants.
Causes of hedge diseases and pests
Generally, all hedge plants can be affected by fungi and pests, but weakened plants are especially susceptible to them. With proper care and under suitable conditions, you will support the hedges' defenses and protect them from disease.
Hedge diseases are usually caused by the following:
Unfavorable location: Too much or too little sun; waterlogging; drought; improper soil pH
Incorrect care and pruning: Too little or too much fertilizer; prune in full sun; prune too deeply for conifers
If these causes can be ruled out, you are most likely dealing with a fungal or pest infestation.
Fungal attack on hedges
Even with proper care, fungal infestation cannot be completely avoided and can damage even hardy hedge species. The following types of fungi are particularly common. Occur on many plants.
Symptoms Flour-like, white and later brownish coating on the leaf surface, which can be easily wiped off. The infested leaves dry up. Whole plant parts can die. In advanced infestations, the fungus spreads to the shoots, flowers and buds. Cause Powdery mildew spreads quickly in dry, warm weather. Mabmeasures Remove the affected leaves and branches. To avoid further infection, also dispose of fallen leaves and always keep the ground around hedges clean.
Leaf spot disease
The name is a generic term for a number of fungal diseases that can only be distinguished microscopically. Fortunately, controlling fungal infestations is possible without such detailed analysis.
Symptoms Brown, black, red, gray or yellow spots on the top of the leaves, which vary depending on the pathogen species. The spots are round, 3 – 6 millimeters in size and have a bright spot – the actual fungus – in the center. In case of heavy infestation, the spots run into each other, the foliage dries out and dies off. Cause The fungi Alternaria, Ascochyta and Septoria are predominantly responsible for staining. Fungal infestation can occur in dry and warm (Alternaria, Septoria) or cool and moist (Ascochyta) weather, depending on the causal agent. Spores are cold-resistant and are transferred to host plants through infected seed or with wind and water. Mabmeasures In case of fungal infection, cut off the affected leaves and twigs.
Animal causative agents of leaf spots
Leaf spots can also be a sign of animal pests in the hedge, such as spider mites. Examine the plants for sticky substances or insects on the underside of the leaves or branches.
Pests of hedges
Visual changes and declining vigor in your hedges can be caused by an insect infestation. Pests prefer already weakened plants and suck or nibble on leaves, stems, or roots. Most of the time, the insects can be seen with the naked eye: They sit on young shoots. Under leaves or fly up when touched. The effect of the infestation depends on the type of insect. Progress of infestation as of.
It is often sufficient to rinse the infested plants several times with a strong jet of water. Beneficial insects, such as ladybugs and ichneumon wasps, birds or plants with intense scents, such as lavender and thyme, also help.
A nettle broth is a natural pest control tool: cover 1 kilogram of fresh nettles with 10 liters of cold water and let the whole thing ferment for about 24 hours. Spray the hedges with the undiluted solution. In case of extreme infestation, chemical agents help. For the sake of the environment and beneficial insects in your garden, use only gentle agents such as neem or canola oil.
Protect your plants with precision prere sprayers
mealybugs and cicadas
Curled-up leaves and honeydew can also be a sign of mealybugs and cicadas. These pests can also be easily rinsed off or, if heavily infested, controlled with neem oil or nettle broth.
Symptoms Tiny insects that grow only up to 0.8 millimeters in size. Depending on the season, they take on a greenish-yellow, red or brown color. Spider mites live on the underside of leaves and feed on the cell sap, causing bright spots to form on the top of leaves. Some species of spider mites cover the leaves and shoots with a fine, white web. Cause These pests are most active during dry, warm periods. Mabmeasures Plants that receive regular watering, aeration and balanced fertilization are less susceptible to spider mites. To control the pests, spray the leaves and shoots from all sides with rape or neem oil. It forms a fine oil film under which the spider mites suffocate. Alternatively, the following mixture may help: Mix 50 milliliters of canola or olive oil with 5 liters of warm water. Pour 200 grams of tansy as a tea. Add this to the oil-water solution. Spray the plant with the agent. If pest infestation is advanced, remove affected plant parts.
Symptoms The beetles leave cove-like feeding marks by eating holes in leaves, shoots and buds. They are nocturnal and rest under stones or foliage during the day. Chubby weevils grow to about 10 to 12 millimeters long, with brown, black and sometimes yellow coloration. Their cream-colored larvae do much more damage to plants and can even cause their death: they live underground and nibble on the roots of the host plant. They bite through the fine roots in particular. Gnaw off the bark of the main roots down to the wood. As a result, the plant dies. Cause The larvae of the beetle are often carried into the garden with new plants. Mabmeasures To control the larvae, pour nematodes, available in specialized stores, into the soil. These are tiny nematodes that poison the larvae of the black vine weevil with a special bacterium, but are harmless to humans. Against the beetles themselves it helps to spray the hedges with neem oil. However, you should not use the two methods at the same time, because the oil is also deadly for the nematodes. To prevent infestation, inspect the root balls of new plants for larvae when you buy them.
Hedge specific diseases
Some hedge diseases occur only in certain plant species. Below we have compiled for you how to recognize and control diseases, fungi and pests in cherry laurel, thuja hedges or conifers.