Mint is one of the most well-known herbs. The numerous species and varieties are just as diverse as their aroma and pleasant fragrance. But what to do if the mint leaves get white spots?
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White spots on mint leaves
If your mint suddenly gets white spots, there are fewer care mistakes than pests and diseases. We therefore present the most common causes and the most promising countermeasures here.
pests as a cause
Pests often visit the mint and then cause white spots there.
Cicadas are one of the most common causes of such leaf spots. These flying insects, two to four millimeters in size, are very mobile and have enormous jumping power. At the slightest disturbance, they run, jump or fly away.
- punctate white spots or speckles on leaves
- caused by the sucking activity of the animals
- white spots appear at the puncture sites
- Cicadas and larvae sit on the underside of leaves
- white spots first on leaf veins
- spread over the whole sheet
- white irregularly shaped formations can be seen in places
- the shed membranes of the larvae
- Affected plants are weakened, but do not die
Control is difficult, but not necessary in most cases, the damage is usually tolerable. If these animals still bother you, you can capture some of them with sticky yellow boards or stickers, for example. If necessary, you can also hose down the plants with a water hose to remove the pests.
It is advisable to lure natural enemies of cicadas such as predatory mites, sciatica, ground beetles, parasitic wasps , lacewings and their larvae as well as birds into the garden. This can be achieved, for example, by setting up nesting boxes , bird baths and insect hotels, as well as by creating flower meadows and/or piles of dead wood. In addition, pesticides should be avoided completely and only sprays that are gentle on beneficial insects should be used.
white bow tie
Another cause of white leaf spot is the whitefly. They can be recognized by a white waxy coating covering their bodies. If you look closely, you will also discover their jumping legs on their abdomen. Their larvae are yellow, unable to move, sit under the leaves and suck plant sap. Mint leaves are also a food source for adult animals.
- small white leaf spots and a layer of wax on the underside of the leaves
- Leaf tops are mottled with yellow
- Mint leaves dry up and fall off
- sticky honeydew is characteristic of an infestation
- sticky substance serves as food for some beneficial insects
- but can lead to diseases such as blackspot
There are several ways to combat these pesky suckers. First, you should remove and discard any part of the plant that has eggs, larvae, or honeydew on it. Self-made spray solutions promise additional help.
Made from rapeseed oil and water
- one part canola oil and three parts water
- mix both together
- Spray affected plants generously with it
- Oil clogs the insects’ respiratory openings and they die
- Spray again after a few days
- if necessary several times
Lye from curd soap
- 40 g of soap and a liter of water
- First grate the soap into small pieces
- then completely dissolve in a liter of water
- Before applying, cover the root area with foil
- Lye should not get on the floor
- apply to affected parts of the plant
- Leave the mixture to work for a maximum of one hour
- rinse with clear water
- from 100 g fresh tansy herb and 1 liter of water
- ideally flowering tansy
- The active substance content is highest in the flowers
- alternatively, dried cabbage is also possible
- Put the cabbage in the water and simmer for half an hour
- strain after cooling
- Dilute broth depending on infestation
- in the case of a light infestation, one part broth to ten parts water
- in the case of severe infestation, one part broth and six parts water
- Spray affected plants generously with it
- Frequency of spraying dependent on success
Tea made from basil
- two tablespoons of fresh basil , a liter of water
- or dried herb
- Pour boiling water over cabbage
- leave for about ten minutes
- let cool and strain
- Spray the plants with the tea
- possibly also several times
As a precaution, you should ensure that the mint is optimally supplied and that it is in a well-ventilated location and change it more often. In addition, it is advisable to combine intensively scented plants with the mint, as they can drive away the whitefly. This can be, for example, thyme, sage, basil, but also marigolds .
diseases as a cause
Causes of white spots on the leaves can also be diseases such as powdery mildew, both real and downy . Both differ in terms of their harmful symptoms.
- Powdery mildew in dry and warm weather (fair weather fungus)
- initially small white spots on leaf surface
- grow rapidly and merge into one another
- Mint leaves, then coated with a white mealy topping
- Downy mildew loves moisture
- consequently occurs in humid and warm weather
- Infestation starts on the underside of the leaves
- with whitish-grey spots
- yellowish spots on the upper side of the leaves
- Affected plant parts die off
- Both species also spread to flowers and stems
- Field horsetail broth also promises help
- effective against downy mildew
- Infuse 30 g of the herb in two liters of water for a day
- then simmer for half an hour
- drain and let cool
- Mix one part broth with five parts water and spray
milk and water
- Mix one part raw milk and nine parts water
- Spray plants with it several times a week
- Lactic acid bacteria act against the fungus
prevent powdery mildew
As a precaution, you should ensure a well-ventilated location, sufficient planting distances and resistant varieties. Also, the mint leaves should not get wet when watering. In addition, field horsetail broth can also be used preventively.