A common pesticide used increasingly in recent years for crops such as corn and soybeans is the likely culprit of the destruction of honeybee colonies around the world, a study released Thursday by researchers at Harvard School of Public Health has found. The researchers said they found “convincing evidence’’ of the link between the pesticide known as imidacloprid and honeybees abandoning their hives, or colony collapse disorder, which they say began occurring in 2006.