Identification Symptoms
- The disease is common in the
     orchards where mealy bug, scale insect and hopper are not controlled
     efficiently.
- The disease in the field is
     recognized by the presence of a black velvety coating, i.e., sooty mould
     on the leaf surface. In severe cases the trees turn completely black due
     to the presence of mould over the entire surface of twigs and leaves.
- The severity of infection
     depends on the honey dew secretion by the above said insects. Honey dew
     secretions from insects sticks to the leaf surface and provide necessary
     medium for fungal growth.