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Is it a Bug or a Fungus?

lace bugs

We’re talking with customers everyday who are concerned that they have a fungus on their plants. My first thought is that it would be rare to have fungus this time of year since its so warm, windy, and dry. It’s much more likely to be a bug. Here’s how to identify and control. 


Is it white and cottony on the stems and flower buds? If so, you have Mealybugs! They show up in the Summer on Hibiscus, Jatropha, Purslane, Salvia and many more of our plants. You can treat with organic Spinosad soap or Bee Safe 3-in1 Garden Spray – be sure to spray in the evening due to our high temperatures. We recommend spraying the plant once a week for 3 weeks. 


Do your leaves look brown and speckled? Sounds and looks like a fungus, but this time of year, its most likely lace bugs on the underside of leaves. They are notorious for attacking Lantana. We’ve even seen some lace bugs on Zinnias and Persimmon trees this Summer. We recommend you cut your plants back one third to half, fertilize and then spray with organic Spinosad soap.

Scale and sooty mold on a Eucalyptus tree

Do your Crape Myrtles look black and sooty? This is a tricky one:  black sooty mold is a fungus, but it’s caused by insects. Aphids, scale insects, and whitefly leave behind a sticky residue (called “honeydew”) that black sooty mold grows on. If you kill the bug, then the soot goes away. Each of these can be controlled with organic Spinosad soap or Bee Safe 3-in-1 Garden Spray.  


Reader Interactions


  1. Mark says

    We’ve noticed an aggressive yellow fungus growing on our potted cabbage (with potting soil) on one lower leaf, on the top of the soil, and growing on the rim of the pot. Any idea what this might be?

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