Essential oils as natural fungicides to avoid pesticide application in garlic crops

ASENSIO C.M.; LUCINI, E. I.; CAMILETTI, B X

Chicago

Congreso; IFT ANNUAL MEETING AND FOOD EXPO; 2016

In many countries, garlic (Allium sativum L.) is widely cultivated and use as a flavoring condiment in foods. The white rot caused by Sclerotium cepivorum (Berk) is the most important disease, with losses up to 100%. Chemical control is the most common way for white rot manegment. The objective of this study was to evaluate essential oils (EOs) as potential fungicides against S. cepivorum in order to avoid the use of synthetic pesticides commonly applied in garlic crops and improve its quality. Five EOs extracted from different aromatic plants grown in Argentina were studied: Tagetes minuta L. (Su), Tagetes filifolia L. (An), Origanum vulgare L. sspp. Vulgare (OCom), Origanum x majoricum (OMen), and Laurus nobilis L. (Ba). The chemical composition of EOs was analyzed by GC-MS. Antifungal activity of EOs was evaluated and minimum fungicide concentrations (MFC) were determined. A phytotocity assay was carried out to identify EO with potential negative effect on garlic. The main components were: anethole (63.80%), estragole (23.81%) and spathulenol (3.26) in An EO; verbenone (28.31%), cis-tagetone (18.73%) and trans β-ocimene (13.40%) in Su EO; 1,8 cineole (42.43%), linalool (15.19%) and Terpinene 4-acetate (8.91%) in Ba EO; o-cimene (14.25%), 4ol-terpinen (12.48%) and thymol (10.86%) and in OCom EO; thymol (27.51%), terpinyl acetate (21.89%) and γ-terpinene (13.92%) in OMen. OMen, with thymol as major compound had the best antifungal activity with a MFC in 300 ppm. OCom was also effective with a higher MFC (800 ppm). However, both essential oil inhibited completely the plant growth and had strong phytotoxic effects. Su had a MIC in 700 ppm but also showed phytotoxic effects on garlic plants. An and Ba showed both moderate antifungal activity with the same MFC (600 ppm) but no phytotoxic effects. These EOs had no negative effect on garlic plants. In conclusion, An and Su could be used as fungicide to control white rot in garlic crops. Industry Relevant text:The use of natural fungicides instead of synthetic ones covers a present trend in crop disease control. Garlic crops could be protected by the use of a natural antifungal agent like An and Su essential oils. The use of these natural products should be considered for the industry as a natural strategy for crop management that could be used in organic food production, increasing quality and giving extra value to the product.