I would say that in the beginning insects would win because we don't have armory to protect against insect bites or attacks.

Then, scientists would make plasma guns and other weapons to kill insects from far. This way, humans will win even without good armory.

But if all countries join together and get lots of special ops soldiers and a gas which makes the insects unconscious, then we can build a huge fleet of human soldiers to match the numerical advantage that insects have.

Vivekanand Vellanki

My take would be that humans would win hands down.

History has shown that whenever homo sapiens (humans) reached new land, within a few hundred years the large mammals in that new land became extinct. This has happened repeatedly in many places to cause people to believe there is a cause and effect relationship - humans land in a new place (e.g. Australia) and large mammals in that place become extinct in a few hundred years.

I would imagine the same would happen with insects. Given the intelligence and machines that humans possess today, they would destroy and kill giant insects in a war. Sure, there would be setbacks, but humans would learn quickly and figure out a way to destroy the giant insects.

Of course, if the insects were endowed with better intelligence, things can be totally different.