To say that growing ornamental sweet potato vines is a piece of cake may be a slight exaggeration, but they are an excellent plant for beginning gardeners. They’re also a good solution for those out-of-the-way spots that you’d like to fill with color, but not mess with too much. Sweet potato vines are very hardy and suffer from few problems, but occasionally white spots on sweet potato foliage appear. It’s unlikely to be a serious problem but read on to learn how to cure a sweet potato with white leaves.
Causes of White Spots on Sweet Potato Foliage
The most common causes of white bumps on sweet potato leaves are edema, mites, and mealybugs, which are all garden problems that are easy to control.
Edema occurs when the water distribution and intake systems in sweet potatoes get out of balance, causing high amounts of water retention. It may be caused by environmental problems, such as high humidity during cool, cloudy weather, or cultural conditions, like over-watering under high light where air circulation is poor. Sweet potato vines usually present with white, crusty growths along their leaf veins that resemble grains of salt on closer inspection.
Control edema in sweet potato vine by controlling the plant’s environment as much as possible. If it’s potted, move it to an area where air circulation is better, discarding any saucers that may be holding water close to the roots. Water the plant only when the top two inches (5 cm.) of soil are dry to the touch – sweet potato vine thrives on neglect – and allow the water to run out of the bottom of the pot. Affected leaves won’t heal, but soon healthy-looking leaves will begin to take their places.
Mites are tiny sap-feeding arachnids, distant cousins to the spiders. Leaves with mite damage often develop a light-colored stippling that may grow into larger bleached areas. Many mite species also leave behind fine silk strands that make identification easier – you’re unlikely to see a mite with your naked eye.
Spray mite-infested sweet potato vines with insecticidal soap or neem oil weekly until you no longer see new damage on your vines. Mites can be kept at bay by keeping dust levels low, a quick spray of water on the leaves of your vines when you’re watering in the morning goes a long way to preventing mite problems.
Mealybugs look like tiny, white pill bugs when they’re moving around on plants and leave behind impressive clumps of white waxy material as they feed. Ornamental sweet potatoes with bumpy leaves may be suffering from mealybugs, especially if white material covers the undersides of leaves and extends to branch crotches. These insects feed on plant juices, causing discoloration, distortion, and leaf drop in severe cases.
Like mites, mealybugs are easily dispatched with insecticidal soap or neem oil. Spray weekly until you stop seeing the bugs. Waxy clumps may be either egg sacs or discarded filaments. Wash these off to prevent reinfestation.