Magnolia Tree - White Spots & Covered w/Bees & Flies

Question: I have a Magnolia tree with white mold-like spots on its bark from truck to branch tips.  Also concerning is the bees and flies.  The tree, bushes, grass, and outdoor furniture under the tree are swarming with bees and flies.  I know this sounds over the top, but the tree is literally buzzing with hundreds bees and flies.  I have not been able to locate a hive or source, and believe that it has something to do with the tree itself.  This tree is beautiful and we want to ensure it's health.  I would appreciate any advice, thank you in advance!

responder: Karolyn  Replied July 22, 2023, 3:38 PM EDT
response: Hello Elaine, From your description, and the picture it appears your tree has an advanced case of Magnolia Scale.  Below I've included an excerpt from a recent extension publication, and some additional information links that include guidance on managing the problem. While scale is seldom an immediate killer of a healthy tree, it can reduce vitality over time. On of the most important things you can do is to simply keep your tree watered when it doesn't rain enough.  " Magnolia scale adults and nymphs insert their piercing-sucking mouthparts into phloem vessels to tap plant sap. As with most soft scales, magnolia scale is seldom a direct killer of established landscape trees. However, a substantial loss of sap from a heavy scale infestation represents a serious loss of energy resources to the trees. The accumulated stress coupled with other stress-producing conditions may cause leaf yellowing and loss; branch dieback and canopy thinning, and even the death of entire trees. Magnolia scale sucks sap to acquire carbohydrates which provide energy. They also extract amino acids which are building blocks for proteins and enzymes. However, the sap only contains trace amounts of amino acids compared to huge amounts of dissolved carbohydrates. This means the scale must process a large quantity of sap to extract the necessary amino acids. They discharge the excess sugar-rich liquid from their anus in the form of a sticky, sugary "honeydew" which is just a nice name for scale diarrhea. Magnolia scale is a prolific honeydew producer. During normal years, the sticky honeydew drips onto the leaves and stems of the host plant as well as understory plants to eventually become colonized by black sooty molds. Although the molds do cause no harm to the overall health of infested trees, the blackened leaves can seriously reduce the aesthetic appeal of heavily infested trees. Management Although significant magnolia scale infestations are rare on native magnolias, the first and best approach to managing this native scale is to reduce tree stress-inducing conditions such as watering trees during a drought. However, fertilizers should be used with caution, particularly high nitrogen applications. Numerous studies have shown that high nitrogen benefits sap-sucking insects by increasing the amino acid concentration in the sap. Magnolia scale infestations attract a wide range of natural enemies including lady beetles such as Sigil lady beetles (Hyperaspis spp.) and Australian mealybug destroyers (Cryptolaemus montrouzieri). Both have wool-coated larvae that are actually wolves in sheep's clothing." https://bygl.osu.edu/index.php/node/1637 https://bygl.osu.edu/index.php/node/1803 https://bygl.osu.edu/index.php/node/937 https://bygl.osu.edu/index.php/node/1986 https://bygl.osu.edu/index.php/node/787 Thank you for contacting Ask Extension,

responder: The Question Asker Replied July 22, 2023, 5:05 PM EDT
response: Hi Karolyn,Thank you so much for your quick and extremely thorough explanation, I think you nailed it!  Your knowledge and resources have been invaluable! Have a great weekend,Elaine  23 at 03:38:20 PM EDT, Ask Extension <<personal data hidden>> wrote: