What episode wiped out many insect species in the world?

Permian extinction

Explanation:

Permian extinction was the one that contributed to the greatest destruction among the five known mass extinction events. Permian extinction is known to occur around 15 million years ago. The extinction wiped out 96% of all marine species and 70% of terrestrial vertebrates and is the largest known mass extinction of events.The extinction led to a loss of the great amount of biodiversity due to which it took a long time for reestablishment of land-dwelling organisms. Several causes have been attributed to this extinction such as - volcanism, anoxia, hydrogen sulfide emissions, etc.