"The long-standing assumption is that fungicides won't be toxic to insects," says May Berenbaum, an entomologist at the University of Illinois Urbana-Champaign. But Berenbaum and her colleagues found, in a study published Monday by the Proceedings of the National Academy of Sciences, that fungicides can harm bees by making it harder for them to metabolize their food.

This week’s topics branch from bing cherry trees and old oaks to fungicide.