The effect of applying Lactobacillus buchneri, alone or in combination with Lactobacillus plantarum, at ensiling, on the aerobic stability of wheat and corn silages was studied in 50-1 plastic containers. Treatments comprised control (no additives), L. plantarum, L. buchneri and a combination of L. plantarum+L. buchneri. After 3 months of storage, the wheat silages treated with L. buchneri had higher acetic acid contents than the control or L. plantarum-treated silages, and were free of mold, whereas the top layers of the control or L. piantarum-treated silages were moldy. In an aerobic stability test the L. buchneri-treated silages were stable, whereas those treated with L. plantarum deteriorated. In the corn silages the effects of L. buchneri were not as clear and the top layer was moldy in all silages. However, L. buchneri also improved the aerobic stability of the corn silage, as indicated by lower yeast numbers, less CO2 production and stable pH. It is concluded that L. buchneri has a potential as a silage additive that protects the silage upon aerobic exposure. The 50-1 plastic containers can serve as an appropriate model to test silage additives before conducting full-scale farm experiments.