Synergistic effect of gamma-aminobutyric acid with avermectin on Bombyx mori

Rapid GABA accumulation is considered a defense mechanism of plants against invertebrate pests. Bombyx mori was used as a model organism to investigate the combined action of GABA with synergists or avermectin against lepidopterous pests. The results showed that GABA had reversible inhibition on the growth and development of Bombyx mori. Synergists TPP, DEM and PBO did not exhibit significant synergistic effect with GABA. In contrast, the mixture of GABA with avermectin enhanced the insecticidal activity of avermectin. The expression of GABA receptor gene in Bombyx mori, BmGABAR, was significantly up-regulated after exposure to the mixture of GABA and avermectin. These results provide a foundation for further study of the rational use of GABA as an insecticide synergist in the control of agricultural pests.