[tossandthrow]

Why would that develop?

The only reason why crops needs to have resistens now is because we treat the entire field with the stuff.

With lasers, you can treat the individual item.

[ulrikrasmussen]

GP wasn't talking about crops, but about the selective pressure that would be placed on weeds to better survive laser attacks. I could imagine that weeds would either develop heat resistance or would change appearance to make detection harder.

[goda90]

Changing appearance to avoid detection is as old a agriculture. In fact it's why we have some foods we enjoy now. https://en.m.wikipedia.org/wiki/Vavilovian_mimicry

[BenFranklin100]

The OP is making a joke.