Leaf Diseases of the Cocculus Laurifolius Hedge

Nutrient Deficiencies

• Nutrient deficiencies can cause numerous disease-like symptoms, from the death of the leaf tips to distortion, loss or color or spotting. A serious deficiency may lead to stunting or branch dieback. According to the UC IPM, nutrient deficiencies are more commonly caused by cultural conditions that reduce the plant's ability to access nutrients. Waterlogged or poorly draining soil is a primary cause. Avoid flooding the soil and apply mulch, which helps reduce soil compaction. You can also apply an even coat of a foliar spray containing iron, applied on a cloudy day with a few drops of liquid soap mixed in to increase stickiness.

Chemical Damage

• Pesticides, herbicides and over-fertilizing can also be toxic to snailseed foliage, causing symptoms such as leaf burn, branch dieback and death on the margins of leaves. If you use herbicides, take precautions so that the chemical doesn't drift into your landscape plants, such as not applying the herbicide on a windy day. Fertilizer is only necessary to correct nutritional deficiencies. Only plant snailseed in a well-draining soil and water regularly, allowing the soil to dry out in between waterings.

Considerations

• Snailseed is extremely susceptible to cottony cushion scale, which may resemble a disease. Scale appear as soft white growths on leaves and twigs, sometimes causing defoliation and twig dieback. Natural predators may not be sufficient to control the pest, as one of the primary predators, the vedalia beetle, avoids snailseed plants. The UC IPM recommends applying a narrow-range, refined horticultural oil in the spring or fall, when young crawlers are active. Mix with water as per label recommendation rates and coat leaves evenly.

Culture

• To help prevent foliage problems, plant snailseed in the proper cultural conditions. Snailseed is best in U.S. Department of Agriculture plant hardiness zones 8 to 11 in a location with good air circulation. Plant in full sunlight or partial shade in well-draining, acidic soil and water regularly. In shady situations, the plant may have a more open, spreading habit. Male shrubs produce pollen that can cause allergic reactions in some individuals. All parts of the shrub are poisonous.