What are the symptoms of mango malformation disease?

Mango malformation disease (MMD) caused by Fusarium mangiferae severely affects the crop and is widely distributed in almost all mango-growing regions worldwide. Additional Fusarium species have also been reported to cause MMD.

It has become one of the most widely distributed threatening problems in mango growing orchards in India as well as in many other mango growing countries of the world.

Abnormal, compact development of shoots and flowers are common signs of mango malformation disease. There are two categories of symptoms. vegetative and floral malformation.

Vegetative malformation is most serious on seedlings and young trees in nurseries, especially where seedlings are grown beneath the canopies of affected trees, but it also occurs on mature trees.

Both normal growth and mango malformation disease–affected growth may be present on a plant at the same time. This includes shorter internodes, dwarfed malformed leaves and an overall tightly bunched appearance of the shoot, while inflorescence malformation includes short, thick and branched axes of the inflorescence.

The symptoms of floral malformation are characterized by deformation of panicles. suppression of apical dominance, shortening of primary and secondary axis. giving the panicle a characteristic clustered appearance, thickened rachis of panicles, and greatly enlarged flowers with large disc and the preponderance of staminate flowers bearing scantly pollen grains.

Floral malformation is most important economically since affected inflorescences usually do not set fruit.
What are the symptoms of mango malformation disease?

Mango malformation

Mango malformation
Mango malformation is widespread in subtropical regions of northern India.

The malformed panicles remain unproductive and are characterized by a compact mass of male flowers, greenish in color and stunted in growth.

The main and secondary rachis are thick and short and bear flowers with relative larger bracts, and petals are compared to normal flowers.

The malformed panicles remain intact on the tress for a considerable period which sometimes extends even to the next flowering season.

Though research efforts made hitherto have not been able to ascertain its etiology, the complexity of the disorder is attributed largely to cultural variation, nutritional, pathogenic, vital and hormonal imbalances.

While comparing the morphactin-induced malformed with healthy and naturally malformed panicles, it was observed that IAA-oxidase activity was higher in malformed panicles and much more in morphactin-induced malformation.

Catalase activity was also low in malformed panicles.

However, it may be pointed out that in morphactin-induced malformation, the bunch was much smaller than in naturally malformed panicle.

Some remedial measures include application of:

• Planofix at the rate of 200 ppm spray followed by deblossoming of early emerged panicles in the in the heavily infested orchards
  


• Deblossoming of early emerged panicles in the months of December and January in orchards where incidence is low.
  


• Avoiding taking a excessive number of scion sticks from the same tree.

Mango malformation