While the compostition of the labor force changed, a lot more people were needed. They need people for year-round work, blossom thinning, limb-tying, and color picking. Also when farmers grew other kinds of apples the growing season got longer which meant they need more people.
Mexicans started to come to America illegally to get a job that pays better than jobs in Mexico. When they started getting large amounts of people they shut down the cookhouse and made people cook for themselves.
Since there wasn't a lot of workers anymore, people would be picked up by buses to be brought to the orchards. They would feed the workers and provide a place to stay. But, some cities were close enough to an orchard were they wouldn't need to provide a place to stay.
The earliest migrant workers were Canadian Indians who, in 1928, only received 40 cents per hour for their fruit picking. Theses Indians came until 1950. They stopped coming because of the bank collapase which caused them to only make 15 cents per hour.