Bay Leaf Plant Has Sticky Leaves with Black Spots
We have a Bay Leaf plant that we keep in a sunroom during the winter and dig into the ground in the summer. We noticed the leaves are sticky. It is growing fine, but some of the leaves have black spots. Should we discard those leaves?
Take a closer look at the upper and lower surfaces of the leaves and the stems. Aphids, mites, and hard shelled scales all suck plant juices and secrete a clear sticky substance called honeydew. A fungus called sooty mold can develop on the honeydew. A strong blast of water will help dislodge some of the mites and aphids. Follow this with a treatment of insecticidal soap to kill these and the immature scale insects. This will also help wash off the honeydew and sooty mold. You may need several weekly treatments to manage the problem. If scale insects are the problem, scrape off any of the hard shelled adults as soon as they are found. Insecticidal soap is safe to use on food plants, just rinse off treated leaves before using. And as always read and follow all label directions carefully. If the black spots are part of the leaf and not a scale insect or sooty mold, you may also have a leaf spot disease. Remove infested leaves and allow the soil to go a bit drier between watering. This is usually enough to control the problem.
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