Safer 16 oz. Concentrate Caterpillar Killer II. It kills a variety of caterpillars and worms, including tent caterpillars, gypsy moths, cabbage loppers, and tomato horn worms. After consuming, caterpillars stop eating and die within a few days. Use in late afternoon or on cloudy days since the BT breaks down in sunlight. It has no effect on birds, earthworms, or beneficial insects when used as directed. OMRI Listed and can be used up until the day of harvest.