The first measure we beekeepers must take is simple: stop cutting the grass in front of the hive! Beekeepers in the Aquitaine region report that long grass hinders the hornet’s hawking and that the bees, on seeing the hornet, quickly dive for the cover of the grass. This recommendation comes from both the Association for the Development of Apiculture in Aquitaine and the Centre National du Développement Apicole.

The second measure is to remove the hiding places from which the Asian hornet launches its attacks. It likes to hide under hives and landing boards ready to ambush incoming bees. Such hiding places need to be screened by sacking or similar material and some beekeepers even attach a ‘beard’ to the landing board akin to Australian corks under a hat. Other beekeepers also screen between hives that are close together.

The third measure is to provide a buffer zone between the bees and the hornet, one in which the hornet’s room for manoeuvre is limited. A common device fitted to the hive is ‘la museliere’, (the muzzle). It is much more than it first appears and it is important to understand why. Fitted to the front of the hive it is designed to screen the landing board but fitting one with a close, 6mm square, mesh size is a mistake. Beekeepers fit that mesh size on the basis that V. velutina cannot get through such a small opening, but the hornets soon learn the trick of snatching the bees when they land on the mesh. All one has done is to move the bees’ landing board out and, in so doing, lost the undoubted deterrent effect of the guard force.

On the other hand, a 13mm square mesh size is more easily and more quickly negotiated by bees, in fact some beekeepers regard an even larger 25mm square mesh as better. Even though the Asian hornet can get through these larger mesh sizes two factors come into play; the hornets cannot fly through even the 25mm mesh and French beekeepers report that they only enter with reluctance, panicking once inside. The guard force realises that its foe is at a disadvantage, adopts the extra space provided by ‘la museliere’, and goes for the hornets, balling them. The beekeeper has exploited a vulnerability in the hornet and shifted the balance in favour of the bee.