Black heart of potato

This was presented by one of the group of students to our Asst. professors Mr. and Mrs. Poudel (Pathology) in 2017. By B.Sc.Ag Paklihawa IAAS campus, Full phase 6th batch

1. Black heart of potato

2. INTRODUCTION Important physiological disorder, storage, transit and market disease caused by poor oxygen relation leading to dark necrotic cavities. Also occur when the temperature goes above 32 C during growth and maturation of tuber and also during transit.

3. SYMPTOMS Symptoms first visible at the center of the tuber. Center of the affected tissue is dark grey to black in an irregular pattern indicating necrosis. Darkened areas are firm but on exposure to room become soft . Advance stage, affected tissue dry out, shrinks with the formation of cavity in the center. Symptoms on reaching the surface appear as dark sunken patches.

4. CAUSES Asphyxiation Storage at low temperature at and below 0 C high temperature (8-10) C. Compact soil which restricts air movement. Prolonged hot or drought period when soils are flooded or stay saturated for longer period oxygen diffusion into potato tuber is restricted. Lack of O 2 to tuber interior causes interior tissue to die and ultimately turn brown purple or black. 2. Low calcium mineral content in the soil.

5. MANAGEMENT Timely and proper irrigation and flooding. Application of calcium rich fertilizer like gypsum and limestone. Maintain moderate temperature during cold storage. Maintain adequate ventilation during transport, storage to avoid asphyxiation.

6. MANAGEMENT Avoid harvesting at extremely heat around 30 c and excessively low temperature around 0 c. Do not delay harvest i.e. timely harvest. Plant variety resistant to heat stress e.g.. Atlantic variety is must susceptible while Harley Blackwell is most resistant.