Dead bees at Hayes Valley farm in San Fransisco.

In late July 2010, up to 200,000 honeybees, kept in hives and dutifully producing honey at the Hayes Valley Farm in San Francisco, were massacred. That might seem like strong language, but how else might one describe the act of spraying pesticide directly into the entrances and ventilation holes of three beehives?

In June, two more hives were destroyed, this time at a different urban farm in San Francisco, Alemany Farm. Instead of a chemical killer, these 70,000 bees succumbed when broken concrete and tree limbs were hurled onto the hives from above, shattering the structures.

These two incidents may or may not have been linked, but they are related insofar as they are part of a troubling pattern of vandalism against urban apiaries. "The worst problem tends to be when, say, two 14-year-olds walk past some hives and say 'I dare you,'" says Kim Flottum, a bee expert and publisher of Bee Culture magazine. "But," he adds, "malicious vandalism is also increasing for various reasons. That's the ugly side of human nature."

It is ugly, yes. But it's also detrimental to the urban beekeeping and urban farming movements and a growing concern among apiarists.