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POSTERS: Chemical control

Evaluation of Isotianil, Isotianil + Fosetyl-Al and Bacillus subtilis QST713 on Coffee Leaf Rust and Brown Eye Spot in Coffee nursery plants
Carlos Angel - CENICAFE, FNC Colombia. Paola A. Rodríguez G.- Bayer S.A.

Resistance induction is an alternative to explore within the integrated management of Coffee Leaf Rust (CLR, Hemileia vastatrix) and Brown Eye Spot (BES, Cercospora coffeicola) diseases, which cause severe defoliation at nursery stage, and yield losses at productive stage. This work evaluated Isotianil, Isotianil + Fosetyl–Al, and Bacillus subtilis QST713 (Serenade®) from Bayer S.A., to control CLR and BES in Coffea arabica cv. Caturra 6 months old plants at nursery stage, under different environments and pathogen inoculum pressure. Initially, products were applied in three doses every 2, 4 and 6 weeks and compared against a reference inducer Acibenzolar-S-methyl (ASM), a fungicide Cyproconazole, checks applied with water, and a non-applied control. In vitro tests for H. vastatrix urediniospores showed that Isotianil + Fosetyl–Al and Serenade® totally inhibited germination, Isotianil allowed 48.3% germination and ASM 9.6%, in contrast to 83% in the water check control. No effect on diseases incidence, but severity reduction were obtained with Isotianil + Fosetyl–Al for BES, and Serenade® and Isotianil for CLR, when applied every two weeks. Following experiments showed increases on foliar area and biomass as fresh and dry weight, and lower defoliation; however, shaded environments conditioned disease reduction and plant responses. Time course assays and disease distribution indicated that resistance induction was mainly local within a short time response (one week), limiting application of these inducers from the coffee farmer and commercial management perspectives.