In the never-ending war on insect pests, the widespread soil bacterium Bacillus thuringiensis (Bt) is one of the greatest heroes. Insecticidal crystalline (Cry) proteins and vegetative insecticidal proteins (Vips) from Bt are treasured for their effectiveness against some devastating pests and their safety for beneficial insects, wildlife, and people (1). Sprays containing Bt proteins have been used for more than 70 years and remain valuable in organic and conventional agriculture, forestry, and vector control (1). Crops genetically engineered to produce Bt proteins were introduced 20 years ago and quickly became a cornerstone of pest management. They have suppressed pest populations, reduced reliance on insecticide sprays, enhanced control by natural enemies, and increased farmer profits (2–4).