Vapors of Essential Oils from Boreal Forest Plants: A Potential New Tool for Controlling Postharvest Gray Mold of Tomato Fruit.

Botanical pesticides, natural pesticides that are derived from plants, and notably essential oils (EOs), represent a potentially effective, eco-friendly, and safe alternative to conventional pesticides. This study evaluated in airtight glass chambers the effect of EOs from different boreal forest plants on Botrytis cinerea mycelial growth and on the development of tomato gray mold, a disease caused by B. cinerea. EO vapors from Labrador tea, black spruce, jack pine and, to a lesser extent, from sweet gale and balsam poplar were shown at a concentration of 200 µL/L of air to significantly reduce B. cinerea mycelial growth. At concentrations varying from 20 to 200 µL/L of air, EO vapors from Labrador tea, black spruce, and jack pine significantly influenced B. cinerea growth kinetics in a dose-dependent manner. Mycelial growth of B. cinerea was strongly delayed in the presence of vapors of either EO at concentrations of 100, 150, and 200 µL/L of air. Exposure of tomato fruits to the vapors of tested EOs at 50 µL/L of air was shown to significantly inhibit the development of gray mold. EO from Labrador tea was particularly effective by completely inhibiting (during the exposure period) the development of the disease when applied at a concentration of 100 µL/L of air. GC-MS analyses revealed that the main compound present in the vapors produced by the EOs from black spruce, Labrador tea, and jack pine was α-pinene (42%), sabinene (59%), and α-pinene (79%), respectively. This study suggests for the first time the possibility of using EOs from boreal forest plants as botanical pesticides to repress B. cinerea mycelial growth and to control tomato gray mold.