Baculoviruses are the only viruses being used as the safest biological control agents. They infect insects and have narrow host ranges. Bacillus thuringiensis (Bt) is the most widely and successfully used bioinsecticide in the integrated pest management programs in the world. Practices that are often compatible with biological control include cultural controls, crop rotation, insectary plantings, trap crops, planting pest-resistant varieties, using approved insecticides with selective modes of action, or spot treatments that leave untreated areas to serve as refuges for natural enemies.