|I live in Florida and both my Gardenia's have a black soot all over the stems and leaves. What can I use to stop this thanks Mike
|Answer from NGA
March 9, 2010
|If the black substance is shiny and can be scraped off with a fingernail, or washed off with water, it is sooty mold. This substance is the result of insect feeding higher up in the plant. As insects such as aphids feed, they exude a sticky substance called honeydew. There is just enough sugar content in the excretion to grow mold and the substance is then called sooty mold. Insecticidal soap is effective against aphids so once you get the aphid population under control you shouldn't have any more problems with sooty mold. Other insects can feed on gardenia leaves so carefully check the undersides of the leaves and the petioles where the leaves meet the stems. Scale or mealybugs might be present. Best wishes with your gardenias.
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