Recently an agricultural services firm was retained to spray the herbicide Milestone VM on nearby pastures to kill clover and other broadleaf plants. After spraying, rains washed some of the herbicide downhill from the pastures into the ponds below. Before the spraying, the ponds were full of tadpoles. A few days after spraying, there were no tadpoles in the ponds examined. Because none of the tadpoles had legs before the spraying, they could not have developed into adult frogs and walked off. Nor could any predator have managed to get every single one of them. And a “control group” — waterways not affected by pasture runoff — still had the tadpoles they had before this spraying. Adult frogs may have been killed as well…