Calcium and potassium contents in nutrient solution on Phoma leaf spot intensity in coffee seedlings

Abstract

Coffee is one of the main export commodities of Brazilian agribusiness. Phoma leaf spot [Phoma tarda (Stewart) Boerema & Bollen] is one of the most important coffee fungal diseases in Brazil. Therefore, this study aimed to evaluate the intensity of Phoma leaf spot in coffee seedlings supplied with different rates of Ca+2 and K+. The study was conducted under controlled conditions in a growth chamber, at the Department of Phytopathology - UFLA, from February 2010 to December 2011. The assay was repeated twice under the same conditions. The nutrient solutions consisted of five concentrations of K+ (3, 4, 5, 6, 7 mmol L-1) and Ca+2 (2, 4, 6, 8 and 10 mmol L-1). The experiment was arranged in a randomized block design, with 25 treatments and three replicates, with two plants per plot. The areas under incidence progress curve (AUIPC) and severity (AUSPC) were calculated. At the lowest rate of Ca2+ (2 mmol L-1) and highest K+ (6 and 7 mmol L-1), approximately, the AUIPC was the smallest. For the AUSPC, the lowest rates of Ca+2 and K+ resulted in the lowest severities. Supply of Ca+2 and K+ in nutrient solution reduced AUIPC and AUSPC of Phoma leaf spot, and these nutrients can be recommended for the management of the disease.

Low concentration fertigation solution allows greater macronutrient use efficiency in coffee seedlings

“…In addition to the ionic form, the relationship between the nutrients may affect the susceptibility of coffee plants to diseases. In C. arabica seedlings, the higher K:Ca ratio (6-7 mmol L -1 :2 mmol L -1 ) reduced the incidence of leaf spots caused by Phoma tarda (Catarino et al, 2016).…”

Differences between the Leaf Mycobiome of Coffea arabica and Wild Coffee Species and Their Modulation by Caffeine/Chlorogenic Acid Content

“…Of these, only Phoma and Fusarium are known to cause coffee diseases. Phoma causes Phoma leaf spot [32], and Fusarium is the causative agent of coffee wilt [33]. Other important pathogens for coffee, such as Cercospora and Hemileia, were not detected.…”