The USA had changed a lot since the 1920s. People had to be 16 and over to work in the orchards or anywhere for that fact. People could go home for the winter and still get paid for that time period.
researchers found out that the fruit was being picked too late due to the lack of workers. so the orchard owners sped up the picking process by putting more people to work. this increased the production.
people were no longer clamoring for jobs so the orchard owners had to find new workers in order to fill the void of people. so people would move from place to place in the seasons.