Healthy Valencian rice grains were sterilized superficially with sodium hypochlorite (20%) for 5 min, rinsed twice with distilled water and air-dried at room temperature (25 ± 2°C). Then the rice seeds for each tested fungus were dipped into a flask containing 50 mL of a spore suspension of 5 × 105 conidia/mL prepared in water-Tween 20 (0.1%) for 30 min. Finally, they were air-dried to complete dryness.
Then the rice caryopses inoculated with the mold were placed inside 150 × 150 mm2 plastic boxes, with 100 seeds per box. Two concentrations (300 and 600 μg/mL) of the Thymus serpyllum EO were prepared in Tween 20 (0.1%)/agar 0.25%. Then 5 mL of each solution were sprayed onto boxes. Seeds were wetted with the prepared solutions and dried to complete dryness, and a fine coating formed. The control was prepared similarly to the EOs assay with equal amounts of sterile water/Tween 20 (0.1%), but without the T. serpyllum EO. All the boxes were then transferred to storage at 28°C at high relative humidity (90-95% RH) for 20 days. The percentage of infected rice grains was recorded after 15 and 30 days of incubation with an Olympus SZX10 magnifying glass.
Then the rice caryopses inoculated with the mold were placed inside 150 × 150 mm2 plastic boxes, with 100 seeds per box. Two concentrations (300 and 600 μg/mL) of the Thymus serpyllum EO were prepared in Tween 20 (0.1%)/agar 0.25%. Then 5 mL of each solution were sprayed onto boxes. Seeds were wetted with the prepared solutions and dried to complete dryness, and a fine coating formed. The control was prepared similarly to the EOs assay with equal amounts of sterile water/Tween 20 (0.1%), but without the T. serpyllum EO. All the boxes were then transferred to storage at 28°C at high relative humidity (90-95% RH) for 20 days. The percentage of infected rice grains was recorded after 15 and 30 days of incubation with an Olympus SZX10 magnifying glass.