Title: Effect of elevated atmospheric CO2 concentration on the incidence of rust and leaf miners, and growth of coffee

Abstract

Earth’s climate has undergone changes in recent decades as a result of the intensification of anthropic activities, which alter the concentration of certain environmental components, such as the atmospheric carbon dioxide (CO2). The present study aimed to evaluate the effect of increasing atmospheric CO2 concentration on plant growth, as well as on the incidence of coffee leaf rust (Hemileia vastatrix) and leaf miner (Leucoptera coffeella) in coffee trees (Coffea arabica) cultivated for three years in a free air carbon dioxide enrichment (FACE) facility. The experiment was conducted at ClimapestFACE facility which was controlled and monitored through a wireless sensor network and established at Embrapa Environment. The CO2 injection was performed until a concentration of 200 µmol mol−1 above the current concentration was reached in the center of the plots. The control plots were kept under current ambient CO2 concentration. The evaluations of plant height and diameter, number of leaves per branch, and incidence of coffee leaf rust and leaf miner were carried out in 2013, 2014, and 2015. Growth of coffee plants (total number of leaves per branch, height and diameter of the stem) was higher under elevated CO2 concentration when compared to the ambient CO2 concentration. The incidence of leaf minor was lower under elevated CO2 concentration when compared to the ambient CO2 concentration. No difference was observed in the incidence of coffee leaf rust between the two conditions considered.