1.   Careful timing and choice of chemical can greatly enhance the effectiveness of a natural enemy.

2.   Cats and dogs have always been natural enemies.

3.   In classical biological control, a natural enemy is introduced to control an organism that has become a pest in its absence.

4.   Much more can be done to improve the conservation of natural enemies in the field.

5.   Reactive techniques like reorganization, retrenchment, and restriction are the natural enemies of organizational innovation.

6.   The pesticide killed off weevils and other insects, leaving the army worm to multiply unchecked by its natural enemies.

7.   The plant toxin renders both the caterpillar and the adult butterfly particularly repellent to natural enemies.

8.   This rabbit had no natural enemies in the Antipodes, so that it multiplied with that promiscuous abandon characteristic of rabbits.It overran a whole continent.