Identifying Harmless Molds versus Bug Infestations
By Laurelynn Martin and Byron Martin
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| Piper Betel Exudates |
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Clerodendrum Speciosissium |
Sooty molds are not harmful and, in fact, are a natural occurring phenomena found on certain plant varieties. Airborne molds colonize on plant sugars and create black patches often confused with leaf pathogens. Little white beads are excreted on the backsides of the leaves and stems. The white beads have a high sugar content and make room for opportunistic molds to colonize; this turns the white beads to black beads. Let us assure you, the beads that we are talking about are not symptoms of bugs or plant diseases. Believe it or not, the molds are harmless.
Symptoms of Plant Exudates
Little white or black beads, Droplets of clear liquid and Black Patches.
How does the mold form?
Some plants are more susceptible to molds such as Piper betel, Clerodendrum speciosissimum, Malvaviscus arborescens, Thunbergia laurifolia and Pavonia multiflora. Plants such as Clerodendrums have glands on the back of the midrib of the leaves where sugars are excreted in tiny patches as droplets of clear liquid. Harmless sooty molds colonize on the sugars, thrive and turn black.
How to identify?
Use a magnifier to see if there is evidence of adult insects. Do not be confused by the exudates that look like insect eggs. Clear white dots and honey dew often seen in heavy infestations of scale, aphids and mealy bugs must have an adult insect for proper identification, else consider it the sugars. Once black appears, you can be assured sooty mold is afoot.
Do you treat for Mold?
No, don’t treat. It is a normal occurrence. The molds may look awful but the good news is all the activity appears on the backside of the leaves. Remember the plants are not harmed from having these opportunistic molds.
Are there any other similar symptoms?
Yes, edema can cause similar but not identical symptoms. White hair-like growth and a resulting black are symptoms of edema, which will be addressed in a later article.