Watching tourists from western Europe for many years, I have come up with the ultimate weapon against their armies, no matter how sophisticated. Spray them with a little bit of honey diluted in water, and release swarms of either bees or wasps a few seconds later. No army from western Europe would have a chance. They would scream for help all the way to their ignoble defeat. And they would suffer from all sorts of mental disorders many years after the horrifying war. Bees and wasps can sting you!