Disinfection of cuttings with eucalyptus oil on yield and disease control of Peruvian carrot<br/>Desinfecção das mudas com óleo de eucalipto na produção e controle de doenças da mandioquinha-salsa

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.O objetivo do trabalho foi estudar o efeito de doses e tempos de imersão em óleo de eucalipto (Eucalyptus globulus Labill.), utilizado na desinfecção das mudas, na produção e no controle de doenças da mandioquinha-salsa ‘Amarela de Carandaí’. Foram avaliados nove tratamentos (0,45%/18”; 1,05%/18”; 0,45%/42”; 1,05%/42”; 0,75%/30”; 0,075%/18”; 1,425%/42”; 0,45%/3” e 1,05%/57”), no delineamento experimental de blocos casualizados, com quatro repetições. As mudas (rebentos) foram selecionadas, imersas nas soluções conforme os tratamentos e deixadas para secar. No dia do plantio, os rebentos foram cortados horizontalmente na parte basal e colocados no fundo dos sulcos, com o ápice para cima. A colheita foi realizada aos 229 dias após o plantio. Os maiores estandes iniciais e finais foram sob as doses de óleo menores que 1,0% e tempos de imersão variando entre 3” e 42”. A interação dose de óleo de eucalipto e tempo de imersão das mudas influenciaram significativamente as produções de massa fresca de folhas (2,49 t ha-1, sob 0,30%/0,02”), rebentos (2,32 t ha-1, sob 0,38%/33,26”) e raiz comercial (3,32 t ha-1, sob 0,44%/39,21” ) e as massas secas de coroa (0,38 t ha-1, sob 0,76%/36,57”) e de raiz comercial (0,65 t ha-1, sob 0,20%/17,9” ). As mudas de mandioquinha-salsa devem ser desinfectadas com óleo de eucalipto em doses menores que 0,5% e com imersão na solução em torno de 40”, para obter-se menor incidência e severidade de doenças foliares e maior produção de raízes comerciais