I returned to the business office this week from a weeklong staycation to various requests from householders to identify a thriller ailment impacting the magnolia trees in their landscape.
A very little diagnostic do the job disclosed colourful, waxy, bumpy growths on the trunk and branches, and a black, dusty material on the leaves, foremost to 1 conclusion: magnolia scale with sooty mold.
Magnolia scale (Neolecanium cornuparvum) is one particular of most significant and most noticeable scale bugs in our Ohio landscapes. Never heard of scales? Although they truly really do not resemble most insects that we visualize influencing trees in the landscape, scales are a type of insect.
Generally showing as a elevated place on tree branches and trunks with a delicate and shiny tan-brown or even a bit delicate-orange coloring and easy outer layer, they effects their host by inserting needle-like, sucking mouth components to obtain the sap discovered inside of.
This form of problems weakens branches and expanding twigs, stunting advancement. Leaf advancement could also stop building a thinning cover. Growing scales are often coated with a white mealy wax and can also look white in coloration and fuzzy in look. Continual feeding and heavy infestation can kill a mature tree.
A secondary challenge with insect scales is that they secrete excess plant sap as a crystal clear sticky compound known as honeydew. As the scales feed, the honeydew drips and coats close by foliage and branches, offering the best ecosystem for the growth of a black fungus known as sooty mould.
Sooty mould is deemed harmless and a lot more of nuisance in most circumstances but can confirm a problem when it fully addresses the leaf floor, hindering photosynthesis. An contaminated magnolia can soil anything at all positioned beneath it with the honeydew, particularly benches, birdbaths, backyard art and sidewalks. The honeydew can also entice ants, bees, wasps and flies that like to feed on it.
The principal goal of this insect pest is the assorted species of magnolia. Saucer, star and lily magnolia kinds are the most usually affected and are most prone to significant infestation. Other customers of the species this kind of as cucumber tree and southern magnolia are fewer very likely to be impacted by magnolia scale.
Magnolia scale winters on 1- to 2-year-aged twigs as very small, dim-coloured nymphs. In the spring as temperatures heat and sap starts to movement, the scale nymphs molt and get started feeding. Males remain modest (about ⅛ of an inch) and convert a translucent white. Woman scales are greater, and by early June are a brownish-purple color and by early summer time turn yellowish-brown and turn into included with their acquainted white waxy coating.
During late July and August, grownup females give beginning to their young, which are recognized as crawlers. The very small crawlers emerge mobile and start on the lookout for a ideal feeding web page wherever they will feed and continue to be by way of the winter season.
When there are numerous predator and parasites recognised to magnolia scale, they are normally not successful at suppressing the populace.
Effective command and administration of magnolia scale requires three key techniques: acquiring pest-free crops, utilizing summer time (horticultural oils) or dormant oils and typical chemical command possibilities.
Treatment method tactic need to be matched to the most vulnerable phase of insect enhancement. The most helpful timing is when crawlers are freshly settled in late August to early September. Soil drenches utilizing systemic insecticides labeled for scale manage in early Could also supply an great solution for control.
For far more data on magnolia scale and sooty mildew, check out out the following assets:
Ohio Condition University Extension Point Sheet ENT-61-Magnolia Scale https://ohioline.osu.edu/factsheet/ENT-61
University of Kentucky Extension Entomology-ENTFACT-431-Magnolia Scale https://entomology.ca.uky.edu/ef431
Buckeye Property and Backyard On the web: Be Warn to Magnolia Scale
https://bygl.osu.edu/node/1803
Buckeye Lawn and Back garden Online: Magnolia Scale is Puffing Up and Dripping Honeydew
https://bygl.osu.edu/node/1316
For guidance with diagnostics, make contact with your community Master Gardener Volunteer Method or Ohio State University Extension business office.
To uncover your neighborhood Master Gardener Volunteer Software, visit https://mastergardener.osu.edu/about/ohio-mgv-county-courses
To locate your local extension office, visit https://extension.osu.edu/lao#county .
Heather Neikirk is a Stark County Extension educator in agriculture and pure methods for Ohio Point out College (OSU) Extension. OSU Extension is the outreach arm of the Higher education of Foods, Agriculture and Environmental Sciences (CFAES) with an place of work in just about every of Ohio’s 88 counties. If you have questions about healthful food items techniques, farm to college, food creation, smaller farms, women in agriculture or food gardening, get in touch with her at 234-348-6145 or neikirk.2@osu.edu.