Creationists: If evolution doesn't exist, how do you explain antibiotic/pesticide/herbicide resistance?

All creationists believe that God created the DNA with a significant ability to adapt within certain boundaries. We agree that God created doglike animals from the Pekingese to the Great Pyrenees. The gene pool of any given kind of animal has enormous but boundaried flexibility. We know there are boundaries [which Darwinists deny] because scientists have produced [manipulated, exposed to radiation and chemicals] 10s of thousands of generations of fruit flies... and they still have only produced fruit flies. At the point where the fruit flies get really weird they no longer can reproduce, but they are still fruit flies. Not even a transitional form of fruit fly halfway to a house fly has been produced. Darwinists, like yourself, are stymied by these boundaries.... yet you cling to the creation myth of the 20th century... Darwinism.