What Is Wrong With My Silk Oak?

Are the leaves yellowing, wilting and, dying?

Do the leaves have spots or blotches?

Do the leaves have white, cottony clusters on them?

Are the leaves and twigs covered with small, armored insects?

Is there a black, sticky residue on the plant, small, white, cottony insects are present?

Yellow leaves that wilt and die usually indicate Root rot disease. Poorly drained, overly wet soil promotes rot so choose well-drained sites and add organic matter to improve drainage. Remove and destroy infected plants. Solarize the soil before replanting.

Your plant is suffering from a fungal leaf spot. These can come from several fungus diseases, causing spots to occur on foliage. Spots may enlarge rapidly, especially in wet weather. Destroy infected leaves or plants. Spray plants with sulfur to prevent the disease from spreading, especially if the weather is wet. Spray between rains. Prevent problems by thinning plants to provide good air circulation.

White, cottony clusters on leaves are caused by mealybugs. These tiny insects are covered with a fluffy white coating. They feed by sucking plants sap. They produce the sticky substance honeydew which makes leaves sticky. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.

Small, armored insects on leaves and twigs are armored scales. These tiny, shelled insects often feed on the undersides of the leaves, causing an unhealthy appearance with yellowish blotches on the upper leaf surfaces. Scrape off minor infestations with your fingernail. Prune out badly infested growth, or use a soft brush and soapy water to gently scrub the scales off the stems. Control scales by spraying insecticidal oil during the growing season.

Cottony cushion scales leave a black, sticky residue behind after feeding. Cottony cushion scale damages a tree by sucking sap from the leaves, twigs, branches, and trunk. Infestations can cause a tree to become defoliated and cause dieback of the tree. Scrape off minor infestations with your fingernail. Control scales by spraying insecticidal oil during the growing season.

Mineral deficiencies can cause tip chlorosis or necrosis or cause foliage to discolor, fade, distort, or become spotted, sometimes in a characteristic pattern that can be recognized to identify the cause. When nutrient deficiencies occur, nitrogen and iron are the most commonly seen deficiencies. Apply only the mineral found to be deficient. Excess nutrients, on the other hand, causes symptoms like leaf tip dieback, marginal leaf chlorosis, necrosis (or burn), branch dieback, and pest problems. In this case, you should provide good drainage, and use good practices during fertilization and irrigation.