Validation of black spot [(Pseudocercospora purpurea (Cooke) Deighton] management strategies in avocado crops in northern Tolima (Colombia) Tekijä Rodríguez-Polanco, Eleonora, Reina-Noreña, Julian Alberto, Tamayo-Molano, Pablo Julian, Rodríguez-Polanco, Luz Astrid, Varón-Devia, Edgar Herney