While you’re preparing the grill for burgers and steaks, the magnolia scale is preparing its young to hatch and unleash on your magnolia trees. Once they hatch is the best time to have your trees treated with insecticides manage the severity of a magnolia scale infestation. The following are 3 things you need to know about the magnolia scale so you can protect your trees this year!
Signs of an Infestation
While you are outside enjoying the nice weather, take some time to examine your magnolia trees. Once you know what to look for, it’s easy to identify a magnolia scale infestation Here are 5 identifiers:
• You have a magnolia tree.
As the name suggests, magnolia scale attacks magnolia trees. There is one variety that they tend to avoid – the sweetbay magnolia.
• You notice a sticky substance on your tree, car, or sidewalk.
When the magnolia scale feeds, it produces what is known as “honeydew”. This is the insects’ excrements.
• You see ants, bees, and wasps swarming the “honeydew”.
The sweet substance attracts other insects that feed on it.
• You see black fungus on the trunk and leaves.
A black sooty mold grows on the sticky “honeydew”.
• You see a large scaly insect.
The magnolia scale is around 1/2 inch diameter – large enough to see. They are often in clusters.
How they Spread
The magnolia scale produces one generation per year. On average, females lay eggs in mid-summer which hatch in late August. Depending on the growing degree days (GDD), the timing may fluctuate year-to-year. The GDD is an indicator used to predict the development of plants and pests.
When the young scale emerge, they have six legs and are highly mobile. At this stage they are known as “crawlers”. Crawlers migrate to branches that are a year or two old to feed and overwinter.
When to Treat Infestation
The magnolia scale is notorious for being difficult to get rid of completely. Generally, it takes several years of applying insecticides to eradicate a heavy infestation. The adult magnolia scales have soft shells, but protect themselves with a waxy substance that insecticides cannot penetrate.
Therefore, the best time to have your trees treated is during late August through September when the crawlers are active. We recommend two applications several days apart in order to target crawlers that may not have emerged before the initial spray.
Now that you know the signs of a magnolia scale infestation, how they spread, and when to treat an infestation, you can protect your trees by being proactive. Call Ahlum & Arbor Tree Preservation if you have questions or would like to schedule an appointment! We have knowledgeable Plant Heath Care (PHC) professionals on staff that can help answer your questions.