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The oleander, botanically Nerium oleander, is not only very popular with us humans, but unfortunately also with small, yellow lice. Because for them, the Mediterranean beauty is the preferred host plant. And once a yellow louse has been discovered, it only takes a short time for an entire colony to develop. To prevent the plague, a daily check is part of the care of the plant. If you have discovered an infestation, you must act quickly, preferably with the following home remedies.
The yellow lice, which prefer to nest in the oleander, are not a special type of lice, but aphids. However, the yellow aphids have specialized on the oleander and other plants from the dogbane family (Apocynaceae), which also includes Nerium oleander.
The yellow aphid, also known as the oleander aphid, is plump and one to two millimeters in size. Their body is dark yellow and their feet are black.
tip: Aphids form so-called aphid colonies, but they can also occur individually.
In the case of aphids, there are only female animals. It is reproduced by the so-called virgin birth (parthenogenesis). In other words: you clone simply, whereby the animals do not lay eggs but give birth to their offspring alive. The generation of offspring is described by experts as explosive, because the lice have often colonized most of the plant within a few days. If there is overpopulation or if the aphid colony is disturbed, the insects emit an alarm scent. This causes the yellow aphid to start producing winged offspring immediately. They then leave the colony and look for a new host plant.
Yellow aphids, like green and black aphids, feed on the sap of the plant. They suck the plant out. They insist on this with theirs bristles penetrate deep into the plant tissue and suck the sap from all parts of the plant, even from the roots. The yellow lice need the protein from the plant sap for their nutrition; they cannot utilize the carbohydrates contained in the sap. These are excreted by the louse and leave a sticky substance on the plant called honeydew.
At the beginning of the infestation, aphids settle on the undersides of the leaves and the young parts of the plant, i.e. on leaf shoots and young buds. Later, however, the lice also sit on the older, non-lignified parts of the plant. The excreted honeydew first covers the shoot tips and leaf axils, but spreads to other parts of the plant as the colony grows. The damage picture also includes:
- discoloration of the leaves
- curling of the leaves
- drive abnormalities
- deformed flowers
Although an infestation with aphids ultimately leads to the death of the plant if left unchecked, the danger posed by honeydew is often much greater. Because honeydew is a sugary solution that serves as a breeding ground for viruses and fungi, such as the dangerous ones sooty mold. For this reason, many experts consider honeydew and the associated virus and/or fungal infestation to be a deadlier threat to Nerium oleander than the yellow aphids themselves. You can identify fungal or viral infestations by the dark brown or black color of the honeydew.
tip: If ants appear on the oleander, this is not a good sign. Because they feed on honeydew and in return protect the colony from predators.
Combat yellow lice
Anyone who hopes for help from the natural enemies of aphids with yellow aphids will unfortunately be disappointed, because the yellow aphids have them defense mechanisms developed against their predators. On the one hand, there is their yellow color, which is supposed to signal danger. On the other hand, and this is the more effective defence, they absorb the highly toxic cardiac glycoside oleandrin with the plant sap. Depending on the concentration, this poison leads to deformities or disturbed behavior in the predators.
Yellow aphids are a nuisance that poses many deadly threats to oleanders, so they must be fought early. In addition to toxic pesticides, there are a number of home remedies that you can use to combat lice. However, in order for them to work effectively, you need to use the funds more often.
tip: When controlling aphids, the sooner the better. If individual parts of Nerium oleander are already infected with the yellow aphids, or if a fungus has already settled, then you should cut off the affected parts of the plant generously.
Targeted hosing down with a hard jet of water has two effects. On the one hand you clean the plant from the honeydew and on the other hand you remove the yellow aphids from the plant. So that the lice do not fall on other parts of the plant, you should hold a pot or bucket under the sprayed areas.
tip: Before hosing down, cover the substrate with a film so that the lice do not fall onto the soil.
If, after a careful examination, only a few yellow lice are found on the oleander, you can also crush them with your hand or a damp cloth. Remember to wipe off the honeydew as well.
tip: When using this method, be sure to wear gardening gloves to protect the skin from oleandrin irritation.
To make sure that the infestation with the yellow louse is really contained, you should treat the oleander with other home remedies to get rid of the plague
Splashing with soapy water is that First aid measure in case of yellow lice infestation. A solution of water with soft soap, curd soap or washing-up liquid is suitable for the soapy water. To do this, add a teaspoon of soap to a liter of water. Mix the two components gently and then pour the solution into a spray bottle. After spraying the infested areas with the soap solution, the oleander lice can be easily removed. In any case, repeat the procedure in the next two to three days.
tip: Since the soapy water is not exactly healthy for the oleander, you should make sure that as little as possible gets into the soil during treatment. Therefore, you should cover the soil with plastic.
Mixture of rapeseed oil and water
For the rapeseed oil-water mixture, add 300 milliliters of rapeseed oil to one liter of water. Shake the mixture well and spray the plant with it. The aphids suffocate due to the oil film in the water.
tip: Compared to soapy water, the rapeseed oil-water mixture is healthier for the oleander.
Nettle stock and nettle liquid manure
You can use dried or fresh nettles to make nettle stock. For every liter of water there are 100 grams of stinging nettles. When extracting with cold water, leave the nettles in cold (rain) water for 12 to 48 hours. When extracting with hot water, the nettles must first be soaked in water for 24 hours. Then the broth with the leaves has to simmer for about 30 minutes. When the brew is ready, sieve off the solid components in both production methods. While the brew can be used undiluted with cold water brewing, the brew has to cool down and be diluted with hot water brewing. The mixing ratio is 1:5 or 1:10.
tip: Nettle brew may only be used if the fermentation process has not yet started, otherwise the brew will burn the leaves.
For the treatment, pour the stinging nettle brew into a watering can with a spray attachment and use it to drain the oleander. The undersides of the leaves are sprayed with a spray bottle. So that the leaves do not burn, you should not use the nettle decoction in direct sunlight. For effective control, the process must be repeated for at least three days. Once all the aphids have disappeared, the nettle broth should be used a few more times as a preventive and final measure. In this way you can be sure that the pests will not return, as the brew does not kill the lice, but drives them away.
Nettle manure is the fermented Form of nettle brew. It develops when the mixture has been in a warm and sunny place for at least two weeks. The fermentation process is complete when you no longer see foam with daily stirring. To combat yellow aphids, the manure must be diluted in a ratio of 1:10.nettle manure
For a tobacco brew you need 50 grams of tobacco from the kiosk or from cigarette butts and one liter of water. It is best to let the mixture steep for a day and then strain it through a cloth. For the treatment, spray the oleander with the tobacco brew for several days.
tip: Nettle and tobacco sand can also be added to the irrigation water. In this way, the brew reaches the upper parts of the plant via the roots and is sucked up by the oleander aphids with the plant sap. That's why it doesn't matter if the brew drips onto the substrate when you spray it.
A mixture of milk and water not only drives away the yellow lice, but is also said to kill them. For the treatment, spray a mixture of 100 milliliters of milk and 200 milliliters of water on the oleander. As with all home remedies, you should carry out the procedure over several days.