Why Does My Acacia Look Sickly?

Are the leaves skeletonized and covered with webbing?

Are the leaf margins notched?

Are the leaves curled and covered with honeydew?

Are the leaves discolored and covered with honeydew, the whole plant look stunted?

Is the growth sluggish, roots are withered, unusually high populations of ants may gather around the base of the plant?

Are the leaves and branches covered with small bumps, cottony masses may be present?

do the leaves have sunken spots?

Are the leaves covered with white powdery patches?

Mimosa webworms are small (up to one inch long), slender caterpillars that feed on leaves and spin silken webs around leaves and stems. They are grayish to dark brown with five white stripes and are sometimes tinged with rose or pink. Young plants may die and the older ones can be seriously weakened. Break up and remove the webs and spray plants with BTK.

Notched edges on leaves are usually caused by insects - Fuller rose beetles. This small, grayish-brown beetle has a cream-colored stripe on each side of its body. It feeds on foliage usually at night time. Larvae usually feed on roots. You can handpick the adults as they hide in foliage during the day. The application of sticky substance at the base of the plant should prevent adults from climbing up the plant. Introduce parasitic nematodes to the surrounding soil to control larvae.

Cause for leaf curling on acacias are psyllids. The eggs and larvae of this tiny insect overwinter on buds and infest new leaves in spring. At the first sign of damage, spray your plant with insecticidal soap, or pyrethrin for serious infestations.

Yellow leaves and stunted look are caused by whiteflies. These tiny, mothlike flies and their larvae feed by sucking plant juices. Whiteflies secrete honeydew, a sugary substance that makes leaves sticky to the touch. Control whiteflies by eliminating garden weeds and by introducing green lacewings in the garden. Spray infested plants with insecticidal soap every 3 days for 2 weeks.

Root mealybugs are small, segmented insects, no more than 1/10 inch long. The tiny insects secrete wax as they feed on the root system of their host plants. They often give birth to live offspring, allowing their populations to explode in a short time. Small plants should be excavated to check the roots for cottony growths or actively feeding mealybugs. Drench the soil with pyrethrin or pyrethroids to control root mealybugs in the landscape.

White, cottony masses, or brownish bumps on leaves and branches of acacia are caused by 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.

Your plants might be suffering from Anthracnose or some other fungal leaf spot. 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. Prevent problems by thinning plants to provide good air circulation.

White, powdery coating on the leaves is caused by a fungal disease Powdery mildew. Powdery mildew usually appears in damp places. Encourage good air circulation around the affected plants by thining any surrounding plants. Water plants from bellow to keep foliage dry. Any affected leaves should be cut off and removed. Any commercial fungicidal spray will protect your plant from further infections.

If the leaves of your acacia turn yellow the problem might be the soil that is too alkaline. Do the soil test, and if the pH is greater than the 7.5 amend the soil with sphagnum peat, elemental sulfur, aluminum sulfate, iron sulfate, acidifying nitrogen, or organic mulches.