Insect apocalypse --
https://www.youtube.com/watch?v=YfTN...NgofSbJQsSfHVd
Rough estimate of a loss of 75% of insects over the last 50 years. That qualifies as a mass extinction.
The predators are most vulnerable to a decline in population and to insecticides. When the predators die off the result is you have an increase in herbivores even though the total number of insects has declined. This is known as a "plague". So one of the consequences we can expect from an insect extinction is great plagues of insect herbivores.