Development of a new dispenser for microbiological control agents and evaluation of dissemination by bumblebees in greenhouse strawberries.

BACKGROUND: To date in modern agriculture biological control strategies are the preferred pest management approach, however, the success of microbiological control agents (MCA) largely depends on an efficient dissemination into the crop. The pollinator-and-vector technology is employing pollinating insects like bees for a better dissemination. Here in this study we developed a new dispenser for bumblebee workers of Bombus terrestris bumblebees; Binab-T-vector and Prestop-Mix were used as two example MCA products.
RESULTS: Firstly, after optimization in the laboratory, the new dispenser is a two-way dispenser 20 cm long with two rectangular compartments and different entrance and exit holes. In addition, the amounts of MCA loaded on the workers were 10 times higher with the new dispenser when compared with an existing system, the side-by-side passageway (SSP) dispenser. Typically, the highest amounts were recovered on the thorax and legs of the workers. Secondly, under greenhouse conditions with use of queen-right B. terrestris hives, successful dissemination in the strawberry flowers was obtained at different distances from the hive (0-8 m, 8-18 m and 18-21 m), and the workers inoculated the first, second and third flowers that were consecutively visited. In addition, the new dispenser caused no adverse effects on worker foraging intensity, whereas a dramatic reduction was scored with the SSP-dispenser. Finally, the data suggested to refill the new dispenser at 3-day intervals.
CONCLUSIONS: The results demonstrated that with use of the new dispenser bumblebee workers carried high amounts of MCA and this resulted in a successful dissemination of MCA into the flowers of strawberry.