Synergistic effect of five spray adjuvants on spirodiclofen 240 g/L suspension concentrate and pyridaben 15% emulsifiable concentrate for the control of Paracoccus marginatusSynergistic effect of five spray adjuvants on 240 g/L spirodiclofen suspension concentrate and 15% pyridaben emulsifiable concentrate in controlling Paracoccus marginatus

The effects of spray adjuvants on physical properties of two insecticides and the synergistic effects against Paracoccus marginatus were investigated in this study. The effects of surface tension, expanded diameter, maximum retention on spirodiclofen 240 g/L suspension concentrate(SC) and pyridaben 15% emulsifiable concentrate(EC) were determined under indoor conditions after the addition of five spray adjuvants (aloe essential oil, silicone silwet408, JFC-2, azone and PBO). In addition, the synergistic effect between the adjuvants and two insecticides were evaluated. The results indicated that the spray adjuvants can significantly reduce the surface tension, increase the expansion diameter, retention and indoor virulence. Spray adjuvants can increase the indoor virulence of spirodiclofen 240 g/L SC and pyridaben 15% EC by 5.1%-26.1% and 22.7%-41.8%, respectively. JFC-2 and PBO were more effective for the increase of the synergistic effects with spirodiclofen 240 g/L SC and pyridaben 15% EC. Field experiments showed that JFC-2 and PBO improved the field control effect of two insecticides in different concentrations against P. marginatus, especially for that in high concentrations. The synergistic effect between JFC-2 and spirodiclofen 240 g/L SC was 10.3%-24.6%, and that between PBO and pyridaben 15% EC was 12.1%-28.9%.