Disinfection of cuttings with eucalyptus oil on yield and disease control of Peruvian carrot

Abstract

The aim of this work was to study the effect of eucalyptus oil (Eucalyptus globulus Labill.) which was used in disinfection of cuttings in different doses and periods of immersion, on yield and disease control of ‘Amarela de Carandaí’ Peruvian carrot. Nine treatments (0.45%/18”; 1.05%/18”; 0.45%/42”; 1.05%/42”; 0.75%/30”; 0.075%/18”; 1.425%/42”; 0.45%/3” and 1.05%/57”) were evaluated in randomized block experimental design, with four replications. Before planting, cuttings (shoots) were selected, immersed in solutions as treatments and left to dry. The adherence of the oil was better using spreader-sticker. On planting day, shoots were cut horizontally at basal part and put at the bottom of the furrows, with their apices to upside. Harvest was done on 229 days after planting. The greatest initial and final stations were under doses of oil that were smaller than 1.0% and under periods of immersion that varied between 3” and 42”. Dose of eucalyptus and period of immersion of cuttings interaction influenced significantly yields of fresh mass of leaves (2.49 t ha^-1, under 0.30/0.02”), shoots (2.32 t ha^-1, under 0.38%/33.26”) and commercial root (3.32 t ha^-1, under 0.44%/39.21”) and dried masses of crowns (0.38 t ha^-1, under 0.76/36.57”) and of commercial root (0.65 t ha^-1, under 0.20%/17.9”). It was concluded that Peruvian carrot cuttings must be disinfected with eucalyptus oil in doses smaller than 0.5% and with immersion around 40”, in order to obtain the smallest incidence and severity of foliar diseases and the greatest yield of commercial roots.