Reducing Potato Foliar Diseases

Nitrogen applications can have the effect of encouraging foliar diseases, particularly applications later in the season which delay maturity, promote excessive vine growth, and increase the risk of blight infection.

Nitrogen excess increases the risk of foliar disases

Nitrogen is an essential nutrient to fuel canopy growth, however in temperate climates, an excess supply of nitrogen at later stages of growth will keep the crop growing, delaying maturity place the crop under increased risk of blight. 

Nitrogen form is also an important consideration as too much ammonium nitrogen is a disadvantage as it reduces root zone pH and thereby promotes rhizoctonia. 

Other crop management practices influencing foliar diseases

  • Ensuring blight spray programs are effective
  • Scheduling irrigation to maximize quality characteristics