Field evaluation of three biopesticides for control of the raspberry cane midge, Resseliella thobaldi (Barnes) in Bulgaria

Abstract

The raspberry cane midge, Resseliella theobaldi is a key pest on red raspberry, Rubus idaeus. The larvae of the insect severely attack the raspberry canes, resulting in premature death of the plant canes. In the last decade, organic production of raspberry fruits has significantly increased in Bulgaria. At the same time there are few products of botanical or microbiological origin that might be used for control of this pest. In present study the effect of NeemAzal® T/C (azadirachtin A), Sineis 480 SC® (spinosad), and Bacillus subtilis on R. theobaldi was evaluated. The experiments were conducted in two raspberry fields at different altitude. In the field at lower altitude (196 m), the raspberry cane midge has developed four generation per year, while in the field at higher altitude (960 m) three generations of the pest have been completed. Lowest number of larvae in raspberry canes was observed after application of NeemAzal® T/C, and B. subtilis in both raspberry fields. Both products demonstrated highest efficacy at 7th day after treatment, when the number of larvae per splits was 67.1-82.5% for NeemAzal® T/C, and 75.1-81.2% for B. subtilis lower compared with the control at the two experimental sites.