Effects of leaf surface and temperature on monocyclic processes in Podosphaera aphanis, causing powdery mildew of strawberry uri icon

abstract

  • Powdery mildew of strawberry, caused by Podosphaera aphanis, is an important constraint to production in tunnels and greenhouses. A better knowledge of the effect of environment on the disease is needed to design efficient management methods. In diseases such as strawberry powdery mildew, the very notion of lesion is difficult to grasp, and progress in disease management has been slow because observations pertaining to the monocyclic processes are difficult and time consuming. Experiments under controlled conditions were conducted to measure the effects of leaf surface (abaxial or adaxial) and air temperature on the different monocyclic processes of the disease. The fraction of germinated spores on the lower (abaxial) leaf surface (0.51-0.84) was 10%-20% larger than on the upper (adaxial) leaf surface. Infection efficiency was 10 times lower on the upper than on the lower leaf surface. Temperature strongly influenced all monocyclic processes considered: spore germination, infection efficiency, latent period, colony size, and colony sporulation. The optimum temperature was 22 degrees C, and no infection occurred at 32 degrees C. Implications of the results on disease management are discussed.

publication date

  • 2009
  • 2009
  • 2009