Fight spider mites on indoor plants

Oh scary! You were just about to devote yourself to your houseplants and suddenly discover fine webs on the leaves and leaf axes: spider mites. The annoying pests of the Tetranychidae family are primarily a hibernation plague and can cause plants to perish within a short period of time. In order to remove the mites, not only home remedies, but also measures to prevent an infestation are extremely important. The good thing: a spider mite infestation can be effectively combated.

Recognize

Before taking any remedy or action, you must be sure that it is really a spider mite infestation. Because of their way of life, the insects are not difficult to distinguish from other pests such as scale insects or black flies. The timing is particularly important, because the animals attack indoor plants from late autumn to spring. The parasites feel particularly at home in the height of winter, when the heating air is dry. The following points will help you to analyze whether the infestation is caused by spider mites:

• "Cobwebs" under leaves and between leaf axils
• light spots on the upper side of the leaf
• Plant is increasingly weak; Stunted stature
• if the infestation is severe, webs on the upper side of the leaf
• Leaves turn light to pale green
• Leaves dry up
• Plant parts die off
• - prone to disease

Spider mite infestation is usually only noticed once they have populated the plant. They reach maximum sizes of 0.8 millimeters, which is difficult to see with the naked eye. The eggs, of which the females lay up to 100, are only 0.1 millimeters in size and, despite their light green color, can only be recognized through the webs. Note that besides the common spider mite (Tetranychus urticae), other taxa do not develop webs. Especially the orchid spider mite (Brevipalpus californicus), which likes orchids (bot. Orchidaceae) and citrus plants (bot. Citrus). Other plants that are particularly likely to be attacked by mites:

• Ornamental ivy (bot. Hedera helix)
• Fuchsias (bot. Fuchsia)
• Sedge grass (bot. Cyperus)
• Rubber tree (bot. Ficus elastica)
• Room azalea (bot. Rhododendron simsii)
• Finger aralia (bot. Schefflera)
• Beautiful mallow (bot. Abutilon)
• numerous palm species

However, the infestation in these plants can be prevented.

tip: The insects also attack plants over the summer, but these are mostly plants that have been planted outdoors.

Prevent

Believe it or not, spider mites on indoor plants are easy to prevent with the right preparation. Since the animals need a very specific habitat, you have to ensure that this does not arise. Your houseplants are found to have eaten if the location, especially the winter quarters, is as follows:

• Temperature 22 ° C - 28 ° C
• low humidity
• high exposure to sunlight

The insects like it warm and dry, which is a typical problem over the winter. For this reason, especially indoor plants are infested over the winter in Central Europe, since the dry ones Heating air and mostly high "feel-good temperatures" are the perfect conditions for a suitable hotbed Offer. On the other hand, the insects do not tolerate weather, moisture and cool temperatures at all. At 16 ° C they stop moving and don't even reproduce.

The following points will help you to keep Tetranychidae away from your crops:

humidity

Be careful not to keep the humidity too low, especially in winter. The dry air is very good for the animals and they continue to multiply rapidly. There are three different methods that can be used to keep the humidity at an appropriate level:

• spray bottle
• wide coasters filled with water
• humidifier

The spray bottle is particularly suitable for individual plants or those that cannot tolerate waterlogging. Use this to spray either the plant or the immediate area regularly. If you choose wide coasters, they should always be filled with a little water. This evaporates and ensures good humidity. With a humidifier you can regulate the humidity down to the percent. This is a good method for you if you don't have a lot of time to spray or change coasters.

temperature

If possible, place the plants in a location where the temperature is below 22 ° C. Of course, this is not possible for many plants, for example tropical plants. Nevertheless, the temperature drop in winter works well against the pests, especially below 16 ° C.

care

Take care of the plant as best you can. If the specimens move weakly into winter quarters, they are at the mercy of the spider mites and therefore the ideal buffet.

Strengthen

If you have delicate plants in your living space, it is recommended that you bring them with you Plant extracts to strengthen. Particularly good protection against Tetranychidae are extracts based on field horsetail (bot. Equisetum arvense), as these strengthen the leaf tissue and are thus armed against the bites of insects. You can create this in the following way:

• 1 liter of water
• 150 g fresh or 15 g dried field horsetail
• 1 head of garlic
• 1 onion (large)
• Splash of rapeseed oil
• Chop the garlic and onions
• add all the ingredients to the water
• Bring to the boil for 15 minutes
• let cool down
• pour off
• fill in spray bottle
• Use from spring to early autumn
• Administer weekly

If your plants are already infested, you can easily use this brew to kill the animals. To do this, wipe the plant thoroughly with the brew over a period of a week until the insects have disappeared.

Preventing the pests doesn't take much work and will save you from a nasty surprise. The houseplants can easily overwinter in this winter quarters without being chosen as a food source by the Tetranychidae. Of course this is the case all year round, but spider mites that sting house plants are mainly found in winter.

Fight

To remove spider mites, there are numerous measures that you can apply effectively and that promise great success. As described above, it is particularly important to make the location of the plant uninhabitable for the animals. Not only home remedies are available for this. However, these are necessary in the case of severe infestation, when clear water is no longer sufficient. In any case, after using these methods and home remedies, you should remove infected parts of the plant with a clean, sharp knife or scissors. This will give you the vitality of the plant.

tip: Many people use cigarette ash to combat spider mites, as the nicotine it contains blocks the animals' airways. However, nicotine is harmful to many indoor plants, which should therefore be avoided.

have a shower

Showering the plant is useful for combating the insects when it is still at an early stage. The fewer mites have populated the houseplant, the more effective this measure is. You only need a waterproof plastic bag for this, as this will protect the substrate from flooding. Pack the plant's tub or pot and make sure it is tightly closed. Now carefully rinse off the plant with the shower head. You can repeat this step several times to shower more spider mites. Above all, take your time with the undersides of the leaves and shoot axes.

Increase humidity for a short time

This method works in the same way as showering, but afterwards provides for a Microclimate in which leftover mites do not multiply or eat on the plant can. This method is particularly suitable for smaller plants, as suitable plastic bags can rarely be found for larger specimens. Proceed as follows:

• Gently rinse the plant
• the pot should not be covered
• The substrate must not be under water
• Pack the whole plant in a clear plastic bag
• leave a crack open

Let the plant sit in the bag for up to a week. The humidity in this increases so quickly that all spider mites are killed. In the meantime, the location of the plant should be adjusted so that it does not re-infest with the pests.

Rapeseed oil

An effective home remedy for spider mites is the use of canola oil. The oil clogs the mites' respiratory organs, causing them to suffocate and easy to remove. The best: only two ingredients are required:

• 1 liter of water
• 250 ml rapeseed oil

Mix these ingredients in a spray bottle and shake well. Now you have an effective spray at hand that can be sprayed directly onto the affected areas twice a week in the event of a slight infestation. If the infestation is worse, you can apply the spray directly to the affected areas with a cloth. Be careful not to damage the plant. Since rapeseed oil does not have an aggressive effect on numerous plants, you can use it without any problems.

Predatory mites

If home remedies don't help, you should rely on predatory mites. This is particularly suitable for winter gardens or large rooms. These insects are natural predators of Tetranychidae, which are offered on cards under the name Phytoseiulus persimilis. In the event of a spider mite infestation, you simply distribute these on the plant and the predatory mites get to work. A single predatory mite eats up to 50 mites and over 200 eggs. At the same time, they continue to multiply, which maintains the natural balance. Predatory mites are also not harmful to your indoor plants. Depending on the provider, you can get this for free or for ten to 15 euros.