Hello! The oleander in the attached photo seems to be attacked by scale insects (Scale insects in ornamental plants - pest management). First of all, it is recommended to remove the severely affected leaves. Then, to control the scale insects, it is recommended to apply insecticide treatments with products such as and , alternately. More precisely, the first treatment is recommended to be carried out with , in a dose of 7.5 ml/10 L water, and 7 days later you can apply the treatment with , in a dose of 3 g/10 L water. To increase the effectiveness of the insecticides, it is recommended to add an adjuvant such as , in a dose of 2 ml/10 L to the solutions. Spray the solutions as finely as possible (), so as to achieve an even distribution on the plant, both on the underside and topside of the leaves and on the stem. After they die, these pests can remain on the stem and leaves, so it is recommended to remove them with a damp sponge. Afterwards, 7-10 days after the end of the treatments, in order to support the regeneration of the plant after certain stressful conditions, or if it has suffered from pest attacks, it is recommended to use a product such as , as recommended in the product description. From spring onwards, and during the growing season, in order to form flower buds and to encourage blooming, it is recommended to regularly apply a fertilizer that is specially formulated for flowering plants: or , applied according to the label recommendations. More details on the care of this plant can be found in the following article:Â https://www.armuro.com/en/oleander-plant-care-growing-guide/.