What Is Wrong With My Chaste Tree?

Do the roots and crowns have dark brown spots at the soil level?

Are there any ring-shaped depressions in the bark that causes twigs to become distorted and swollen?

Are the leaves curled, distorted, and yellow?

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

Did the leaves turn yellow or brown especially along margins and at the tip?

These symptoms indicate fungal disease Phytophthora Root and Crown Rot. Phytophthora pathogens are favored by wet conditions, and the risk of disease can be reduced with good water management. The disease tends to affect plants in poorly drained areas, where susceptible plants are surrounded by standing water or saturated soil for prolonged periods. Provide adequate drainage and know the water needs of individual plants.

Pittosporum pit scale leaves ring-shaped depressions in bark and causes twigs to become distorted and swollen. The scale commonly congregates on the growing tips where plant distortion can be so severe their feeding obliterates the individual pits. Infested leaves may be smaller than normal and twigs may die back. It can be controlled by spraying terminals with horticultural oil in late winter or early spring, before buds open or new leaves are produced. Where infestations are severe, annual application of oil or adding a persistent insecticide may be needed.

Distorted, curled leaves are caused by aphids. These tiny insects can vary in color, green, pink, black, gray to completely white. They cluster under leaves and on growing tips where they feed on plant sap. Leaves, stems, and buds get distorted, and later leaves and flowers drop from the plant. 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.

Chaste trees are susceptible to Leaf burn or scorch. Leaves turn yellow or brown especially along margins and at the tip. They may curl, turn black and die or drop prematurely. Provide plants with a good growing environment and proper cultural care.

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, cause 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.