Whats wrong with my mango tree?

[ACrater]

Is this a nutritional deficiency or some kind of fungus? I already did a foliar spray of KNO3 for potassium deficiency but as you can see in the photos, the tips of new leaves are also turning dark..

 

[Marck]

It does resemble an anthracnose or blight, perhaps Colletotrichum gloeosporioides, but there are other possibilities. Of course, Mango (Mangifera indica) is an important crop in India. Are there local agricultural extension offices where you might inquire? Local agriculturists should be well-informed about local Mango diseases.

Pruning to remove infected leaves and stems anf to allow more light and air movement into the tree is one method for controlling such diseases, but of course there are also fungicides/bacteriacides available, with varying levels of effectiveness and non-target toxicity...

 

[ACrater]

It does resemble an anthracnose or blight, perhaps Colletotrichum gloeosporioides, but there are other possibilities. Of course, Mango (Mangifera indica) is an important crop in India. Are there local agricultural extension offices where you might inquire? Local agriculturists should be well-informed about local Mango diseases.

Pruning to remove infected leaves and stems anf to allow more light and air movement into the tree is one method for controlling such diseases, but of course there are also fungicides/bacteriacides available, with varying levels of effectiveness and non-target toxicity...

Is a carbendazim+mancozeb fungicide suitable for treating anthracnose?

 

[Marck]

Those are both commonly used fungicides, but I do not know what is recommended for anthracnose on Mango, nor do I know for certain that that is what ails your tree. I would not make any personal recommendations regarding fungicide usage, but I do urge caution and consultation with local professionals for both diagnosis and treatment options.