dissolved separately in 0.5 mL of 5% (v/v) Tween-20 was pipetted asepticallyonto filter paper discs of 4 cm diameter and respectively placed into individual weighing bottles (ϕ 40 × 25 mm) without lids to obtainfinal concentrations of 0.05, 0.1, 0.15, and 0.2 L/mL air