Palm trees are members of the Cyad family and are often found in many home and commercial landscape designs.These plants add a tropical flair to any home garden or indoor setting. While palm trees are generally hardy, they are susceptible to diseases and environmental factors that may cause spots to develop on the fronds, or leaves, of the palm.
Sago palms are common additions to many outdoor landscape designs. Evergreen leaves are feathery and whorl around the trunk of the tree. Native to Madagascar, sago palms are slow-growing trees that can eventually reach a height of 6 feet. Ponytail palms are another type of palm tree found in both indoor and outdoor landscapes. Members of the Agavaceae family, ponytail palms are characterised by their wide trunks, which earned them the name of elephant foot tree. Ponytail palms are fairly easy to care for and should be repotted frequently to avoid becoming root bound.
Causes of Spots
If your outdoor sago palm develops white spots on the fronds, it could be herbicide damage. When spraying herbicide products on your lawn grass for weeds, it is possible for overspray to damage your palms. Once herbicides cause white or yellow spots on palm leaves, the foliage does not regain its normal green colour in these areas. Both sago and ponytail palms are sensitive to the effects of the sun. Too much sunshine can cause a condition known as sunscald, which is characterised by light-coloured spots on the foliage of the plant. Sunscald is especially common when palms have been transplanted to a less shady location or moved near a window inside the home.
Some other causes of leaf spots can be leaf spot diseases, underwatering and overwatering. Dehydration usually causes leaves to appear discoloured in spots or along leaf margins. Infestations of insects such as the red palm mite can cause leaf spots to develop on palms. These mites are red in colour and are easy to see on green palm leaves.
Keep your palm trees healthy and stress free to keep spots from forming on the fronds of the plant. Take extra care when spraying herbicides and do not apply when the weather is windy. Place your palms in areas of partial shade to reduce sunscald. Provide your palms with the appropriate amount of water. Overwatering is a common cause of root rot in ponytail palms, and underwatering can place your palm under drought stress. Inspect your palms regularly for signs of insect infestations. Spider mite feeding causes white or yellow specks or stippling on the leaves. Spider mites can be removed by spraying your palm tree with a forceful stream of water two or three times each week.
Herbicide damage will not go away once it occurs on your palm. Chemical control products may be helpful in controlling root rot diseases and leaf spots on palm trees. When red palm mites are plentiful, horticultural oil products may help control them. Oil products work by covering the mite with oil and causing it to suffocate and die. A variety of predatory insects feed on palm mites and help keep their population low.
- University of Arkansas: Sago Palm
- University of Arkansas: Ponytail Palm
- National Gardening Association: White Spots on My Palm Tree
- University of Florida; Guidelines to Identification and Management of Plant Disease Problems; Monica Elliott, el al.
- University of Florida; Red Palm Mite; Marjorie A. Hoy, et al.