Knowledgebase
Laurel Bushes - Q re possible infectio #757335
Asked June 20, 2021, 6:52 PM EDT
I have a few laurel bushes. After they stopped flowering a brown dirt like substance has shown up on top on the leaves. No powdery substance. Is it a fungal infection? See pictures
thanks
Baltimore City County Maryland
Expert Response
Hello; Thanks for submitting your garden and landscape questions to UMd Ask Extension.
What I see in your photograph are flower debris resting on the tops of your laurel plants. Apply a jet-stream of water to the foliage of your laurels to dislodge and wash this off.
There maybe some sooty mold remaining on the tops of leaf foliage. This could be the product of insect scale feeding on the foliage and plant stems of your laurels. Look for a white grainy substance on the stems of your laurel shrub which is likely 'prunicola scale'. See University of Maryland Extension publication https://extension.umd.edu/resource/armored-hard-scale-trees-and-shrubs.
If you see this scale pest in your laurel plants you might want to apply horticultural or neem oil directly on stems and leaves of your shrub, but DO NOT APPLY OILS when temperatures are above 85F degrees. Wait until there are a few days when temperatures are consistently below 85F before applying oil sprays to your plants. And it may be necessary to reapply oils to your plants to give adequate coverage.
Good luck with your landscape plants. Christopher