POSTERS: Chemical control
Preliminary screening of resistance inducers to control Coffee Leaf Rust (Hemileia vastatrix Berk. & Br.) at nursery stage in Colombia
Carlos Angel - CENICAFE, FNC Colombia. Juan M. López-Vasquez- CENICAFE, FNC Colombia, Alvaro Gaitan- CENICAFE, FNC Colombia
Coffee Leaf Rust (CLR) is still the most important coffee disease worldwide, causing severe defoliation, yield and quality losses up to 50% in susceptible varieties. Considering that, 19% out of 887,000 hectares planted in Colombia are CLR susceptible, additional alternatives to chemical fungicides for integrated management are required. Thus, several products considered as resistance inducers were tested in 6 months old Coffea arabica cv. Caturra plants at nursery stage, which were based on Acibenzolar-S-methyl, Harpin protein, Salicylic acid, Potassium phosphite, Copper peptidate, Glucosamine, Phosphated sugars, Potassium silicate, citrus essential oils, and two naturals. They were applied once at 15, 30 and 45 days before CLR inoculation in three doses, within a factorial and randomized design. CLR severity was quantified 30 days after inoculation, and ANOVA analysis and Tukey tests (?=0.05) were conducted. All products and doses significantly affected CLR urediniospores germination at in vitro assays, the two naturals and Glucosamine caused the lowest inhibition, and Salycilic acid, Harpin protein, Acibenzolar-S-methyl and Potassium phosphite inhibited between 100% and 84.3% germination. All products had significant impacts on CLR severity averages, ranging from 2.97% for Potassium phosphite to 1.08% for Acibenzolar-S-methyl, in comparison to 8.45% for the water negative control. Most resistance inducers reduced CLR severity when applied at recommended or high doses at short time intervals, and varied in local and systemic responses depending on the product´s nature.