The red spider is also called the fruit tree spider mite. It particularly likes to attack grapevines, apple and pear trees, plums, gooseberries and currants. You have to know that there is another pest that looks similar and that the two are often confused. It is the red velvet mite. But it belongs to a different genre.
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Spin mites are difficult to control. The red spider is no exception. It is important to discover the infestation as early as possible and to initiate countermeasures in good time. The more these pests can spread, the more difficult it will be to get rid of them.
The red spider overwinters in the ice stage and is therefore already sitting on site as soon as it gets warm in spring. Then most of the spider mites hatch and are sexually mature from May, at the latest from June, and begin to reproduce. The plague begins.
The females of the red spider are about half a millimeter tiny and brick-red. They have very characteristic white bristles on their backs, which of course cannot be seen with the naked eye. For this you need at least a good magnifying glass or a microscope with good resolution. A female lays around 20 to 40 eggs, several times a year, and up to seven generations grow. The eggs are laid in small groups on the underside of leaves. They are extremely small. Only larger groups can be seen under the magnifying glass.
Recognize spider mite infestation
The pests can be recognized by the fact that even after they have sprouted, dark leaf tips are initially noticeable. Dark stitches can be seen on freshly unfolded young and tender leaves, of course best under a magnifying glass. The leaves hardly develop any further, stay small, bulge upwards and finally fall off. In summer they turn bronze-brown.
If you suspect that these spider mites populate a plant, you should take a spray bottle with water and lightly spray the shoot tips, which are particularly likely to be infested, or only spray over these areas. When the water droplets settle, the very fine and delicate webs that the spiders form become visible. The small spray droplets stick to them and make them visible. Often you can see that the entire tip of the shoot is woven into it. With the naked eye you usually cannot see the fine web, only when it takes on proportions and then the infestation is very large.
There is not much that can be done to prevent the pests from migrating. However, you can strengthen the plants so that they can deal with an infestation better, so that they are simply better equipped when they are attacked. You will then not fail so quickly. Plant strengtheners such as nettle liquid or horsetail broth are suitable. The plants are sprayed with it. The two agents are relatively easy to manufacture.
No matter what you do, it’s about working fast. The infestation must be recognized in good time if countermeasures are to be effective. The longer the red spiders can damage a plant, the more difficult it is to control and the less likely the plant will survive.
I did a lot of research and found a wide variety of means and opinions about it. What you should know is, I believe, that spider mites, which the red spider belongs to, are very special. They are arachnids. They belong to the group of insects, but are better combated with an acaricide than with an insecticide. Acaricides are pesticides or biocides specifically designed to control mites and ticks. They are also used in commercial cultivation, especially in fruit, viticulture and horticulture.
Natural predators are ideal for containing the red spider. They include predatory mites, predatory bugs, lacewings and ladybugs. By promoting these insects, you fight pests in the garden at the same time.
Hosed down with water
It is absolutely recommended to shower the infected plant first, regardless of whether it is a houseplant or a fruit tree. It is important to have a hard jet of water and to spray the leaves from below, because the spider mites are usually located on the underside. In this way, a large part of the insects is simply washed away. It doesn’t matter if leaves fall off, you would have done that in a very short time even without a water jet. In the case of indoor plants, it is advisable to cover the soil, preferably to put the whole pot in a bag and tie it to the trunk. If the houseplants are not cared for, pests often attack them, usually when the pot is too wet. Showering would only make the substrate wetter, so it would protect the pot! In the garden you can just hold the water jet on it, there is nothing to pack. The water flows off.
Since you cannot eliminate all pests with a water hose, step two follows. This is where sprays are used. With their help, the eggs and larvae should also be combated. The contact effect is crucial here. The red crawfish have to be sprayed on directly or the active ingredient is absorbed by touching the treated leaf surface. The poison can also be absorbed by eating or sucking the leaf parts. The problem with the individual remedies and control steps is that hardly any one helps against all stages of development. Some group of pests always remains and evolves. This is why spider mites are so difficult to control. Infested plants must therefore be treated once a week for six weeks. So you always kill the newly hatched larvae, they don’t get to reproduce. After 6 weeks the cycle is over, you should have caught all the red spiders.
If you don’t go through these weeks and finish the treatment, the consequences are worse than if you don’t do it at all. The insects become resistant to the agent. Then you can no longer fight them with it, or it has no effect. However, since this may already have happened, experts recommend not using just one remedy, but rather two or three and alternating them.
Many plants do not get along well with the sprays and their effects. In addition, you never get to all parts of the plant and you never catch all of the spider mites. I am not a big fan of pesticides, as they often also act at the expense of other insects, including many beneficial insects. The chemical agents usually make no distinction between friend and foe.
Which sprays are suitable?
The remedies are numerous, but they change quickly in the market. This is due to the fact that new regulations are being issued and the agents or their ingredients are no longer permitted. But there are new ones very quickly. You just have to find out what’s on offer at the moment.
With phosphoric acid esters – oleo-phosphoric acid ester helps against numerous mites, including the red spider. Also works against other stinging insects, such as the aphid. Resistance to these agents develops very quickly.
Special acaricides – e.g. Kanemite ® – are effective against the eggs of the red spiders and protect predatory mites, the plant must be completely moistened. The liquid contains an adhesive (wetting agent) and therefore does not drip off the leaves or the plant. Must be mixed, the adhesive is added separately, that’s how I understand it. Only helps at the beginning of the season. Since October 2013, agents containing acaricides are no longer officially available in stores. You only get remnants. This measure serves to protect the bees.
- Natures Plant Spray Hortex New – Ingredients – Nazur-Pyrethrum and Piperonylbutoxide, also works against eggs, dangerous for bees – 400 ml about 7 to 10 euros
- Spruzit pest-free – ingredients – natural pyrethrins and rapeseed oil, also against larvae and eggs, 250 ml from around 7 euros
- Organic pest-free neem – Ingredients – Azadirachtin A = natural neem kernel extract – only approved for commercial horticulture, partial systemic effect, 60 ml about 10 euros
- Pritex spider mite and whitefly stop – preventive agent, more for plant strengthening – 500 ml about 10 euros
- Lizetan Plus Ornamental Plant Spray – Ingredients – Thiacloprid and Methiocarb, for indoor and outdoor plants – 400 ml about 8 euros
- Zenar (Maag Profi) – a means from Switzerland, against all summer stages of spider mites, active ingredient Tebufenpyrad
Systemically acting means
Systemic agents are either added to the irrigation water or sprayed onto the leaves. These agents are absorbed directly by the plant, passed through the root or leaf surface and through the entire plant. When the arachnids prick and suckle the plant, they ingest the poison with them and perish. It doesn’t matter where you pierce the plant, the poison is everywhere, unlike the spray. It doesn’t go everywhere.
Vertimex, a product with the active ingredient Abamectin, is particularly recommended. However, it is intended for commercial cultivation. However, there are also other remedies for the hobby gardener with the same active ingredient. There it is only in a negligibly low concentration. They don’t work nearly as well.
There are not many systemic agents left. Many have been taken off the market or are not approved for the hobby gardener.
- Vertimec – actually for commercial cultivation, acaricide, emulsion concentrate with abamectin (active ingredient derived from a natural soil microorganism), particularly high potency, good depth effect (remains in the plant for a long time), odorless and leaves no splash marks, expensive – 250 ml for example 85 euros, but Vertimec is a concentrate, it has to be diluted very heavily. The other resources are ready to use and can be used straight away. I recommend sharing a bottle of Vertimec with several people, 25 ml each, if the price goes through 10, you still have enough and in the end you get cheaper than the already diluted bottles and the effect is much better. The fact that this product is not approved for the hobby gardener does not mean that it cannot be bought.
- Pentac – active ingredient dienochlor, has a delayed effect, especially against mites, not available in Germany, Austria and Switzerland.
The best time to fight it is when the mites hatch from their eggs in early spring. If the first generation exterminates before spawning, no more can develop. Pests can still invade, but you are simply powerless against it.
House plants are also often plagued by the red spider. Anthuriums, cobbler palms, begonias, colored nettles, gardenias, hibiscus, wax flowers, primroses, African violets and cineraria are particularly threatened. Chemical pesticides usually damage plants more than the red spider can. Therefore it makes sense to increase the humidity first. The little crawlers don’t like that. However, you have to be careful not to get the earth wet. Also, not all plants like spraying.
Hard-leaved houseplants such as rubber trees can be treated with preparations based on rapeseed oil. The oil clogs the pests’ breathing openings, but also the pores of the leaves. So it is a double-edged sword and may only be used with a few plants and only with an initial, weak infestation.
What you can save:
- Oily products – at least on plants that are not hard-leaved, as the oil not only clogs and closes the pests’ breathing openings, but also those of the plants.
- Predatory mites in the house – they usually only help for a short time.
- Spraying soapy water or the like does not eliminate the problem, it only curbs it for a short time. It is not a permanent solution as it will not work against the eggs in any way.
- Putting the infected plant in a bag, spraying it, tying it and thus creating a microclimate with high humidity does not do much, since the eggs are not damaged here either. The spider mites don’t die either, they just don’t feel comfortable that way.
- Most biological remedies do not help either, as they do not work against the eggs either. Exceptions: Neem products, preparations based on chrysanthemum extract or similar.
The red spider is a nuisance. It breaks a lot of plants and is difficult to control. Once you have finally found a product, it can happen that it disappears from the market the next time you try to buy it. You have to try a lot and change and swap products because of the resistance. The red spider is one of the most stubborn pests of all. I am very happy that she hardly does any more for me. Years ago I also had problems with the nasty little things.