Damage to leaves can provide you with one of the first clues that something is wrong with your jasmine. Insects, diseases and cultural problems can all manifest as symptoms visible on the foliage of your plant. In the case of jasmine (Jasminum species), plants require little maintenance and experience few pest or disease problems. Nonetheless, if you notice something wrong with the leaves of your plant, you know to dig deeper to discover the cause.
Very few pests bother jasmine, but those that do can cause damage to the foliage. Spider mites can infest winter jasmine (J. nudiflorum). These minute pests drain the sap from leaves, causing a yellow stippling on the surface of the leaves. Badly infested leaves may turn yellow or grey in colour.
Soft scales and mealybugs also damage jasmine. Both types of insect drain sap from stems and leaves and produce a sticky residue called honeydew. Honeydew can often cause a secondary infection of sooty mould to form, covering the leaves with black fuzz. Mealybugs form white, cottony masses on leaves and branches. Soft scales can cause leaves to become deformed, yellow or fall from the plant. Insecticidal soaps can treat jasmine pests.
Botrytis mould can infect jasmine plants, damaging the foliage and harming the health of the plant. Leaves begin to die, and you may notice a dark grey, fuzzy mould present on the leaves. Remove and destroy infected plant parts and use a fungicide to control this rapidly spreading infection.
Jasmine doesn't require a lot of fertiliser, but you should plant it in moderately fertile soil. If the soil lacks key nutrients that jasmine needs to grow, it may show signs of deficiency, which frequently cause abnormalities in the foliage. Nutrient deficiencies often cause leaves to turn yellow. The pattern of the yellowing can help you to determine which nutrient you need to add to your soil. For example, nitrogen deficiency causes older leaves to turn yellow, while sulphur deficiency causes younger leaves to yellow first. Nutrient deficiencies can also cause leaves to turn brown at the tips or edges, wilt or develop deformities.
Too many nutrients can cause toxicity. Plants often turn brown along the edges with a thin yellow margin separating the brown from the green of the plant. This damage typically begins at the leaf tip.
Jasmine requires moderate amounts of water, and drought can also cause damage to the leaves. Leaves turn yellow and appear burnt along the edges. Other problems that limit a plant's water intake can cause similar symptoms, such as root damage because of construction, soil compaction or damage from road salts or herbicides.