|hi my gardenias have a black spot on the leaves - it is a pest and is allover the plant - i have now used 8 different types of pesticide spray and the pest still comes back|
|One of the biggest complaints gardeners have about gardenias is their propensity to attract certain insects. Mealybugs, aphids, scales and whiteflies are all problematic on gardenias. Mealybugs are one of the most prevalent gardenia pests and are easily identified as white, cottony masses found in the leaf axils and other protected areas of the plant. Aphids can also be challenging on gardenias. Be on the lookout for a soft-bodied, tear-shaped insect, typically clustered around newer growth and/or on the underside of leaves. Another pest on gardenia is scale which appears as raised brown bumps on the stems and underside of leaves. Whiteflies are tiny pests that can become a big problem on gardenias. Whiteflies are small winged insects which look more like moths than flies. Whiteflies can be prolific and seem to come out of nowhere in what appears to be an instant snowstorm of minute dust-like particles. Not only does whitefly feeding damage plants, whiteflies can also transmit plant viruses.
Insecticidal soap sprays are usually effective against these pests but you'll need to make repeat sprays in order to control the insects. Be sure to apply according to label directions.