Volatile Component Analysis of Michelia alba Leaves and Their Effect on Fumigation Activity and Worker Behavior of Solenopsis invicta

Volatile compounds from mashed (fresh, fallen, and dried) leaves of Michelia alba were collected via solid-phase microextraction and were then identified via gas chromatography-mass spectrometry. The results showed that linalool was the dominant component in different leaves, together with caryophyllene, beta-elemene, and selinene, the contents of which vary across the samples. The fumigation bioassay results showed that the volatiles from M. alba leaves exhibited insecticidal activity against red imported fire ant workers, and the mortality of workers could reach up to 100% after the fallen leaves were treated for 16 h. Mashed fresh leaves could effectively reduce the aggregation and drinking ability of workers. The volatile substances released from the mashed leaves might kill the ants, or affect their behavior and weaken the activity by interfering transmit information between ants. A comprehensive consideration of the economic and ecological value of M. alba shows that fallen leaves might be a good resource to control red imported fire ant.