Efficacy of propiconazole and sanitizers for sour rot control on lemon.

FOGLIATA, G.M.; ACOSTA, M.E.; MARTINEZ, C.V.; MUÑOZ, M.L.; PLOPER, L.D.

Foz do Iguacu

Congreso; International Citrus Congress 2016; 2016

IAC - IAPAR

Sour rot (Galactomyces citri-aurantii) is an important lemon postharvest disease in Tucumán, Argentina. Guazatine, used for its control, is not accepted by the European Union (importer of Argentinian lemon). Therefore, efficacy of sanitizers and propiconazole (Melanite 250) was determined. Sanitizers evaluated were: didecyl-dimethyl-ammonium chloride (Sportak), sodium hypochlorite (SH) and hydrogen peroxide-acetic acid-peracetic acid (Deccosan FH) to control conidia in vitro; SH, chlorine dioxide (CD) and sodium bicarbonate (SB), to control conidia applied on fruit; with or without organic matter (OM); SH to reduce natural load of pathogen on fruit surface in commercial packinghouse; and propiconazole for infection control on fruit treated 18 hours after inoculation. Sportak (1?) and Deccosan (4?) reduced 99% of pathogen (1x106 conidia/ml), with or without OM. SH (200 ppm Cl) and CD (2?) reached this efficacy in absence of MO. A control reduction directly proportional to increased MO was observed. At the packinghouse, 200 ppm Cl reduced 99% of populations with less than 1x102 conidia/ml, and 69% when load was 1x103 conidia/ml (maximum detected). SB (>2%) only inhibited mycelium growth. Propiconazole efficacy was 80% with doses that left residues on fruit of 1.1 mg/kg, whereas efficacy increased to 98% with 1.6 to 2.6 mg/kg (doses 350-500 ml/hl). Effective management of sour rot is possible with proper use of sanitizers to reduce initial inoculum and propiconazole to control infection.