Behavior of rust in new and old inner leaves in Conilon coffee

Abstract

Coffee rust (Hemileia vastatrix) epidemics are studied in detail in Coffea arabica where a single lesion can cause defoliation, in contrast to the same disease in Coffea canephora, in which the infected leaves remain on the plant. The objective of this study was to compare the progress of coffee rust based on its incidence in young and old inner leaves in different genotypes of Conilon coffee. For this purpose, a field experiment was performed in Vila Valério, state of Espírito Santo. The incidence of rust disease was evaluated during twelve months in plant genotypes 143 (ENCAPA 8131), 02 (ENCAPA 8111), G35 (Verdebrás), and Verdinho HP grown in fields. With data on rust incidence collected during one year, it was possible to determine the disease progress curve and calculate the area under disease progress curve (AUDPC) for each genotype. The data were obtained from the young and old leaves and statistically compared. Rust was more prevalent in old inner coffee leaves. The Gompertz model gave the best adjustment to the disease progress curve. Genotype 143 was the most resistant. Infected leaves on the plants could be an important inoculum source to be considered in the management of rust in Conilon coffee.