All Rights Reserved. The honeydew may also draw other insects like ants and wasps to the tree. Mold and ants may be the effect, rather than the cause, of magnolia tree problems. However, sooty mold reduces photosynthesis. A fungal disease called black mildew (Meliola spp.) Sooty mold is often found on or below plants infested with certain types of sap sucking insects, especially aphids and soft scales, which produce a sugary secretion called honeydew. The sooty mold itself usually does not cause a direct problem for your plant but rather an indirect one: Namely, it inhibits the photosynthesis in a plant. You may also see ants crawling on the tree, because they are attracted to the honeydew. Step 2. Learn to Identify and Eliminate Aphids on Your Indoor Plants, 7 Flower Garden Pests That Can Ruin Your Hard Work, Identifying and Treating Leaf Spot Fungus on Magnolia Trees, How to Get Rid of Scale on Euonymus Shrubs. The real causes often are the magnolia scale bugs. The sooty mold itself usually does not cause a direct problem for your plant but rather an indirect one: Namely, it inhibits the photosynthesis in a plant. These bugs also secrete a substance that can promote mold growth and attract ants. Inspect your magnolia tree for sooty mold. Sooty mold symptoms, black powder on leaves. I think it is a bush-type magnolia; in any case it's about 6 yrs. Introducing "One Thing": A New Video Series, The Spruce Gardening & Plant Care Review Board, The Spruce Renovations and Repair Review Board. The dark color is a black sooty mold fungus that grows on the honeydew. old and is about 6 ft. tall. You spray it, let it sit a while and break down the sticky mold then rinse it off with a hose. These insects grow within the thick foliage spread of magnolias without displaying any signs of their early development. The sticky honeydew and black sooty mold are often noticed before the insects are seen. Check the tree above the infected tree, because the honeydew can drip onto the tree or vegetation underneath. Scale insects are commonly the culprit behind this chain of events on magnolia trees. The nymphs are called crawlers in the early stages of life, and they move around for a short period before they hunker down and remain dormant while overwintering. Black mold, or sooty mold, causes aesthetic problems for magnolia trees but does not hurt their growth. Follow the pesticide directions and spray the entire tree. The scale insects secrete a liquid called honeydew that invites sooty mold. Main symptoms Superficial, dark brown or black fungal growth Caused by Fungi, growing on pest honeydew or plant exudates Timing During periods of plant growth and pest activity; may be year-round in conservatories … How to Remove Black Sooty Mold. Magnolia scale excretes honeydew after feeding on the tree. Wasps love honeydew and are also attracted to the leaves, so if your magnolia is attracting wasps, that confirms the scale diagnosis. Sooty mold causes a velvety growth on leaves and bark. Plan the perfect garden with our interactive tool →. And because this honeydew—true to its name—is a very sweet substance, ants like to feed on it. Learn tips for creating your most beautiful (and bountiful) garden ever. Look for sucking insects like aphids, mealybugs, soft scales, leafhoppers, whiteflies and psyllids. David Beaulieu is a garden writer with nearly 20 years experience writing about landscaping and over 10 years experience working in nurseries. Honeydew Damage. Learn which plants thrive in your Hardiness Zone with our new interactive map! Growth may also occur on other objects such as garden furniture, paths, cars, etc. Types of Scale Damage The magnolia scale encrusts the branches of the magnolia tree. These insects drain sap from magnolia plants and excrete a sticky-sweet liquid called honeydew. Wet leaves can encourage other fungal growth. Sooty mold causes a velvety growth on leaves and bark. Black Sooty Mold: Though not a harmful disease, sooty mold is the fungal growth on the leaves and stems of magnolia trees that are infested with pests like scales and aphids. Black Sooty Mold: Though not a harmful disease, sooty mold is the fungal growth on the leaves and stems of magnolia trees that are infested with pests like scales and aphids. Air-born sooty mold fungus attaches to this honeydew and develops quickly into a black layer that covers leaves. The result is that the necessary photosynthesis can't take place, and the health of the plant suffers accordingly.