Is your Magnolia tree turning black? Is it attracting ants, flies, bees and wasps? Is there a sticky substance covering the leaves and everything under the plant? If you look closely, you will also see white blotches on the twigs throughout the tree.
This is an invasion of magnolia scale like we have not seen in several years. They happen to thrive in warm summers with abundant moisture. The population is building and is very apparent this year.
The insect overwinters on twigs and is inconspicuous to the untrained eye until it starts feeding and producing honeydew. Honeydew is the very sweet, sticky substance secreted by the insect that in turn coats the leaves and anything under the plant. This is what attracts other insects to the plant. Eventually the insect covers itself with a waxy coating that protects it while feeding. These are the white blotches we are now seeing on the plants starting mid-summer through August.
Nymphs emerging from a recently plucked adult Magnolia Scale
The insect emerges from these waxy coatings in mid to late August through September as crawlers. This is when the insect is most vulnerable to insecticides. We typically recommend 2 sprays during this period spaced a couple weeks apart for the best control of the insect due to the extended emergence.
The insects feed by sucking sap out of the tree. If left untreated the scale population can grow to levels that will cause decline and eventual death in your tree.
Another issue with Magnolia scale is the occurrence of sooty mold which is a byproduct of the honeydew produced by the scale. It is a black fungal growth which is what most people notice first. Although this generally does not harm the tree, it is very unsightly.
In closing, if you have a magnolia in the landscape, give us a call and we will dispatch a certified arborist to your property to come out and complete an evaluation of the tree and make recommendations for the best management strategy. Timing is everything.
Sincerely,
Mike McKee | Regional Manager, Russell Tree Experts
Mike graduated from Hocking College in 1983 with a degree in Natural Resources specializing in urban tree care. He has been a certified arborist since 1991. Mike started his career in the private industry in 1985 before becoming a municipal arborist in 1989. He retired after serving thirty years before joining us at Russell Tree Experts in Sept. of 2018. His love of trees has never waned since trying to climb up the ridges of the massive Cottonwood tree in front of his childhood home.