Infected plants are characterized by small, soft, thin and malformed leaves with light yellow color. Plants of thorny varieties become smooth and lose their thorns. The plants are generally stunted in growth and have shorter internodes and petioles. They develop an enormous amount of branches and roots than healthy plants which gives them a bushy appearance and hence also known as Witches Broom. The flower parts (phyllody) become deformed and mostly sterile. The developing fruits become hard, tough and fail to mature. As the disease progresses, new growing leaves only grow 1/3 - 1/4 of its original size.
The symptoms are caused by bacteria-like parasites called phytoplasma. The plant-to-plant transmission is mostly through insect vectors, different species of leafhoppers, especially Hishimonas phycitis. It can affect plants in all growth stages.
Beneficial insects such as lacewing, damsel bug, minute pirate bug are voracious predators of both the egg and larval stage of these insects.
Always consider an integrated approach with preventive measures together with biological treatments, if available. Imidacloprid, Cypermethrin and Dimethoate can be used to suppress insect vectors.