Safer Caterpillar Killer II kills worms and caterpillar stage insects but has no effect on birds, earthworms, or beneficial insects when used as directed. 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. Controls tent caterpillars, gypsy moths, cabbage loppers, tomato horn worms, and more. Safer Brand Caterpillar Killer is OMRI Listed organic and can be used up until the day of harvest.