Stilbene-based fluorescent brighteners (FB) have been shown to enhance insecticidal activities of entomopathogenic viruses but little is known its effect on entomopathogenic bacteria. We investigated the effect of two FBs (FB 28 and FB 71) on the insecticidal activity of B. thuringiensis var. kurstaki (Btk) as well as the Lymantria dispar multiple nuclear polyhedrosis virus (LdMNPV) in Lymantria dispar asiatica. FB 28 increased the mortality at the combination with low concentration (1.6×102 IU/ml) of Btk, but FB 71 slightly reduced the mortality with middle and high concentrations (1.6×103 and 1.6×104 IU/ml) of Btk in comparison to Btk alone. Both FB 28 and FB 71 increased mortality in combination with LdMNPV at all concentrations (3×102, 3×104, and 3×106 POBs/ml) compared to LdMNPV alone. Our findings suggest that FBs enhanced pathogenic activities but depend on chemical nature of FBs.

• Lucas Mezione de Carvalho(Department of Applied Biosciences, Kyungpook National Universisity, Daegu, Korea) Corresponding author
• Hwal-Su Hwang(Department of Applied Biosciences, Kyungpook National Universisity, Daegu, Korea)
• Kyeong-Yeoll Lee(Department of Applied Biosciences, Kyungpook National Universisity, Daegu, Korea, Department of Plant Medicine, Kyungpook National University, Daegu, Korea)