Stress
As we mentioned before, pesticide science is a highly controversial field. No matter what side of the issue you're working for, you're likely to run into some very stressful situations.
If you're working for a corporation that wants to put out the most effective pesticide in the least amount of time, you'll not only be dealing with bosses from the corporate office breathing down your neck for results but you may have to sacrifice some of the safety of the product in order to get it on the market. Not to mention the pressure you'll receive to keep it as cheap as possible.
If you work for a regulatory agency, you're likely to get a great deal of pushback from both lawmakers and corporations that want you to ease up on supervision. This could lead to government probes into the work you do, protests from environmentalists who don't think you're doing enough, and much more.
Beyond the monetary and political implications of working in such a field, you'll be working with volatile chemicals in a lab setting much of your time. So you must always remember to take your time, follow all safety procedures, and keep your cool.