The disease is caused by the fungal species Fusarium mangiferae. The vegetative malformation is commonly found on young seedlings. The seedlings produce small shootlets with small scaly leaves, giving it a bunch like an appearance on the shoot apex. Seedlings remain stunted and eventually die. Variation in the panicle can be seen in the malformation of the inflorescence. Heavily malformed panicles are compact and overcrowded due to larger flowers. Affected plants develop abnormality with dense shoots and flowers. Growing points such as leaf and stem buds produce misshapen shoots with short internodes and brittle leaves. Leaves are significantly smaller than those of healthy plants. Normal and malformed growth may be present on a plant simultaneously.
The disease is mainly spread via infected plant material. Excessive soil moisture, mite infestation, fungal infection, virus, herbicides and other toxic compounds aids in the production of fungus. Deficiency of Iron, Zinc and Copper can also cause malformation. The disease spreads slowly within affected orchards. Temperatures of 10 - 15°C support the growth during flowering.
Use leaf extract of Datura stramonium (Alkaloids), Calotropis gigantea and neem tree (Azadirachtin) to reduce the infection. Trichoderma harzianum is also effective in controlling the pathogen's growth. Diseased plants should be destroyed. Use disease-free planting material. Scion sticks from infected trees should not be used.
Always consider an integrated approach with preventive measures together with biological treatments, if available. Captan 0.1% helps in controlling the spread of the disease. Spray insecticides of folidol or metasystox as a control measure. Spray carbendazim 0.1% at 10, 15, or 30-day intervals during the flowering stage. Naphthalene Acetic Acid (NAA) at 100 or 200 ppm reduces the incidence of the disease in the following season. Spraying with trace elements of Zinc, Boron, and Copper before bloom and after fruit harvesting has proved to control or minimize the incidence of malformation.