Leaf blotch is caused by Taphrina maculans and appears as small, oval, rectangular or irregular brown spots on either side of the leaves, which soon become dirty yellow or dark brown.  The leaves also turn yellow.  In severe cases the plants present a scorched appearance and the rhizome yield is reduced. 

The fungus is mainly air borne and primary infection occurs on lower leaves with the inoculum surviving in dried leaves of host, left over in the field. Secondary infection is most dangerous than primary one causing profuse sprouting all over the leaves. The fungus persists in summer by means of ascogenous cells on leaf debris, and desiccated ascospores and blastospores in soil and among fallen leaves

This disease usually appears in October and November. Relative humidity of 80% and temperatures of 21-23°C favours the primary infection. The disease can be controlled by spraying mancozeb 0.2%.

Leaf spot is caused by Colletotrichum capsici and appears as brown spots of various sizes on the upper surface of the young leaves. The fungus produce toxic metabolites which cause necrosis on leaves. The spots are irregular in shape and white or grey in the centre.  Later, two or more spots may coalesce and form an irregular patch covering almost the whole leaf.  The affected leaves eventually dry up.  The rhizomes do not develop well. 

The disease is usually appears in August and September. It is also observed in November in certain areas. The disease occurs when there is continuous high humidity in the atmosphere.

The fungus is carried on the scales of rhizomes which are the source of primary infection during sowing. The secondary spread is by wind, water and other physical and biological agents. The same fungus is also reported to cause leaf-spot and fruit rot of chilli where it is transmitted through seed borne infections. If chilli is grown in nearby fields or used in crop rotation with turmeric, fungus perpetuates easily, building up inoculum potential for epiphytotic outbreaks.

The disease can be controlled by spraying mancozeb 0.2% or Bordeaux mixture 1 %.

Root knot nematodes (Meloidogyne spp.) and burrowing nematode (Radopholus similis) are the two important nematodes causing damage to turmeric.  Root lesion nematodes (Pratylenchus spp.) are of common occurrence in Andhra Pradesh.  Wherever nematode problems are common, use only healthy, nematode-free planting material.  Increasing the organic content of the soil also checks the multiplication of nematodes.

Rhizome flies are black and ant like and lay eggs at the base of the stem. This pest appears from the beginning of October to till the crop is harvested. This pest also infests rhizome rot-affected-rhizomes. After hatching, the flies penetrate into rhizomes and feed the internal content completely.The yield loss due to this pest is 48-50%. Use disease free rhizomes.