Association of essential oils and the coating film of cassava starch in the control of gray-mold in postharvest strawberry

Abstract

Abstract The use of essential oils for plant disease management during the postharvest period has been a difficult task because of the high volatility of their active antifungal components. To reduce the essential oil volatilization, we mixed cassava and cinnamon essential oils in a coating film made of cassava starch and used it to control strawberries gray-mold (Botrytis cinerea) in the postharvest period. Chemical characterization revealed that eugenol was the major component in both essential oils with levels > 76%. In a preliminary in vitro assay, the essential oils showed a significant reduction in mycelial growth rate as well as a reduction in sporulation. Furthermore, in the confirmation in vivo experiment, in which we evaluated disease development for four days in strawberry fruits inoculated with B. cinerea, a decrease in disease infection rate was observed when the coating film was applied alone, compared to the control check. No disease was observed when essential oils were applied in association or not with the coating film, thus we were not unable to evaluate whether or not the coating film could increase the time of action of the essential oils. On the other hand, in the fungicide treatment without coating film, the disease reached ~ 80% severity on the fourth day of evaluation, however, fungicide in associating with the coating film totally inhibited disease development. Based on these results that the use of the cassava coating film has a promising effect in prolonging shelf life when applied alone and in association with other chemical control methods.