However, whether or not it is required I suggest that you definitely DO keep records of every drop of pesticide you apply, with basic details on the site of the application. Somewhere along the line someone is going to involve you in a legal issue where you will need to be able to bring forth that information, and if it is readily available it could save you from some serious problems. For example, 2 or 3 or 4 years from now someone could claim they have health issues due to an application you do today, and if you have no records of what was applied to that property, if you applied anything at all, then their accusation cannot be disproved. 

I remember an incident way back in the 1980's when chlordane was about to be eliminated from our uses. A major TV "investigative" journalist did a terribly lopsided report on the horrors of chlordane in homes, leading the EPA (based on that inaccurate TV show) to ban chlordane. One of my customers said he had a homeowner call him a few days later complaining of serious illness due to the chlordane he had applied as a termiticide 2 days earlier. He told me that he was never so happy to be 4 days behind in his work as he was at that moment - he hadn't even done the job yet, but this customer was already getting sick, apparently in anticipation of being exposed. Because he kept careful records of his use of pesticides he easily could have proven that he had not treated this property for termites yet. 

I suspect most states do require that you keep careful records of what you apply, the sites to which you applied the products, the pests you treated for, and the amounts used. In California this information is then reported monthly to each country in which a company is registered to do business. For School Pesticide Use there also are specific requirements for record keeping and these records of pesticides used on a school property must be maintained by the school. I believe the records must be kept for at least 2 years, but frankly I would keep them for far longer than that, and with electronic files it would cost nothing to maintain them form 20 years or more. Similarly any training records you have for employees should be maintained for the entire duration of their employment, and they should receive annual training as required on the various aspects of safety and proper pesticide use.