Power
In this job, it's your responsibility to ensure our food's bug-free-ness, as well as the safety of the food supply that helps to feed millions upon millions of people. So, future pesticide scientist, you actually have a great deal of power. Hopefully you'll use that power for good. Yeah, sure, it'd be really fun to be a supervillain and hold the global food supply for ransom while laughing maniacally, but to what end?
Okay, so realistically you'll only be researching one part of one pesticide (hopefully to find out its negative effects), so you won't exactly have the entire world's food in the palm of your hand. However, your research will probably lead to conclusions being drawn about the safety and/or effectiveness of a certain pesticide. So in that sense, everything you do has the potential to affect the world.
Don't worry, though, the responsibility doesn't fall squarely on your shoulders. You're just the lab rat doing the tests. It's up to the corporations and regulatory agencies to take your work and apply it to real life. Go ahead, exhale.