Whenoleander leaves turn yellow and fall offit may indicate inadequate growing conditions, infection with pathogenic fungi or pest attack. In order to correctly identify the cause and choose the right way to save the plant, it is worth knowingthe symptoms of oleander diseasesand learn to distinguish them. Here are the most commonoleander diseases and how to combat them
Diseases and pests of oleander: (1) frost damage, (2) oleander scales, (3) aphids
Oleander diseases with a physiological background
Oleander diseases with a physiological backgroundresult from improper cultivation conditions or errors in the care of the plant. Excessive watering causesoleander leaves to turn unnaturally green, then turn yellow and fall offbrown discoloration may also appear on them. In turn, with water shortagelower oleander leaves and flowers turn brown and dry
To avoid these problems, remember to water the oleander abundantly (in hot weather, even every day), while providing it with a sufficiently permeable substrate (soil with an admixture of peat and sand) and drainage from pebbles or expanded clay at the bottom of the pot. After watering, remove excess water from the stand under the pot. Also, do not expose the oleander to rainfall (preferably the plant should be in the open air, but under a roof). In winter, the oleander goes into a dormant state and watering should then be significantly reduced.
Whenonly the edges of the oleander leaves dry , the plant is most likely suffering from a potassium deficiency. Then fertilization with fertilizer for flowering plants will help, because this type of fertilizer is rich in potassium.
Strong drafts causeoleander leaves yellowingToo low temperatures and frosts result inlaxity and fading of the shoots and wilting of the leavesTherefore, remember to always place the pot with oleander in a warm place , sunny and sheltered from the wind. In our climate, plants can be exposed from around mid-May, when the risk of frosts is over, and they can stay outside for the longest until October.
Oleander Fungal Diseases
Zoleander fungal diseasesgray mold and leaf blotch are the most common.
The symptom of gray mold iswhite or gray coating on oleander leaves, stems and flowersand in the case of leaf blotchlight brown spots appear on oleander leaves , sometimes with a darker border. Factors that influence the development of fungal diseases are: too high humidity, low temperatures, excessive plant density and over-fertilization.Plant parts affected by gray mold or leaf blotch should be removed and burned. The plant can then be sprayed with a fungicide, e.g. Topsin M 500 SC. If we want to avoid the use of chemicals, in order to prevent the development of both of the above-mentioned diseases, we can use the natural preparation Biosept Active, and in the case of gray mold, also the biological agent Polyversum WP.
Oleander pests
The attack of oleander pests is favored bytoo high temperature (especially in the wintering room) and the lack of ventilation. The effect of the pests isyellowing of the shoots and leaves of the oleander, followed by the death of the entire plant .
Oleanders are often affected by pests from the group of scots (cuplets, scales, mealybugs) and aphids. The symptom of the occurrence of cuplets areflat 2-3 mm brown or black spots on the leaves and shoots of oleander , while in the case of scales they are about 8 mm arched discs.Oleanders, typical for this plant, are characterized by very light-colored discs. Mealybugs are insects covered with white, glomerular secretion. These pot plant pests are removed by hand by wiping them down and washing the shoots and leaves with gray soap or spirit.
The oleander aphids form numerouscolonies of small wingless insects on both sides of the leaves and on the inflorescencesAffected plants grow more slowly and are covered with sticky aphid secretion and black fungus growing on it. To combat aphids on potted plants, natural agents that are safe for use near living quarters are used, such as Emulpar 940 EC or garlic-scented potassium soap.
MSc Eng. Katarzyna Żywot-Górecka
