Commonly called "umbrella plants" because of their large palmate leaves, or "octopus plants" because of the tentacle-like racemes of flowers, Schefflera plants are popular houseplants and can be grown outdoors in USDA zones 9b to 11.
Schefflera trees are long-lived plants that need little maintenance. They grow best in medium to bright light, although they will also grow in low light. Most diseases of Schefflera trees occur in damp conditions. Avoid wetting the foliage and overwatering the plant.
Bacteria Leaf Diseases
The initial symptoms of pseudomonas leaf blight are small, water-soaked lesions on the edges of the foliage of Schefflera trees. The lesions get bigger and turn black, resulting in severe leaf drop.
Irregular corky spots on the underside of the leaves characterize xanthomonas leaf spot. The spots are tan to yellow and turn dark brown.
No effective treatment exists for bacterial leaf diseases. Remove and destroy infected leaves. If the plant is severely infected, destroy it to prevent the disease from spreading.
Fungal Leaf Diseases
Alternaria leaf spot causes large brown spots with yellow halos, which spread and cause premature leaf drop. The disease also affects petioles and stems of Schefflera trees. Phytophthora leaf spot resembles Alternaria, but begins on the lower leaves first.
Collectotrichum leaf spot begins as circular or oval tan spots. The spots turn dark brown and develop irregular edges. As the dead tissue falls out, the leaves begin to curl or cup.
Remove and destroy infected plant material to prevent the spread of diseases. Fungal diseases can be treated with a fungicide approved for Schefflera trees at the rate recommended by the manufacturer. Some fungicides can damage the foliage of Schefflera trees.
A fungus causes powdery mildew, a white, dusty coating on the leaves and stems of Schefflera trees. Remove and destroy affected plant material. If the powdery mildew is widespread, use a fungicide approved for Schefflera trees and follow the manufacturer's directions. The foliage of Schefflera trees can be damaged by some fungicides.