Numerous studies have been done on the toxicity in insects harmful to crops for use as a possible insecticide.

We put beneficial nematodes in the ground to attack the larva of harmful insects.

There were no harmful insects left; the Machine had seen to that.

Goureau was especially devoted to the study of harmful (and later beneficial)insects.

The use of human hands to remove harmful insects or other toxic material is often the most common action by gardeners.

Another possible explanation is that the sudden movement dislodges harmful insects.

With no natural controls, the harmful insects reproduce so rapidly that they soon become immune to the pesticide.

He helped set up measures to control the spread of plant diseases and harmful insects from both within and outside Canada.

DDT was thought to be the 'final solution' to the problem of harmful insects.

They also pray for the elimination of disasters or harmful insects.