Meet the diamondback moth (Plutella xylostella), a tiny insect that ranks as one of the world’s most devastating agricultural pests. Named for the cream-colored diamond pattern on its back, this species causes billions of dollars in annual damage to brassica crops like cabbage and canola. Brassicas defend themselves by releasing toxic compounds when chewed—a chemical defense known as the “mustard oil bomb.” However, diamondback caterpillars have evolved a specialized gut enzyme that neutralizes these toxins, completely disarming the plant. Barely the size of two grains of rice, these formidable flyers can ride wind currents to travel over 2,000 miles during transcontinental migrations. They are also notorious as the first insect to develop resistance against several widespread insecticides. When travelling in Sweden and Finland in the summer of 2026, I witnessed the sheer scale of their reproduction capacity, encountering these little moths by the hundreds every evening.