It has always been my experience that wherever the food source, the beast of the world will find their way. Besides, how many of those bug's fly?

Crops are not the only food source that brings in bugs and birds and vermin. Remember first that bugs are a food source for many animal's, secound, That bugs pretty much go wherever they please and pretty much have the Earth covered with their kind. And they feast on flowers, herb's, vegetables and just any source of plant life that exist's. That includes poisonous plants. The more vegetation that exists in any one area will bring in kind a hundred score of bug's. And with her vision of all the building rooftop's with Those small garden's, it might as well as be a bumper crop for the bug's, bird's and vermin. They'll literally infest the city with virus' and droppings.