 Yes, that was a big list, so here's some more details. By spraying in the morning or when temperatures are fairly cool, plants are more receptive to anything you spray. In the heat of the day, crop leaves often roll up and stomatas close. Even if you can get 5% more fungicide into the plant, that might mean an extra bushel or two, so spray when it's cool. By spraying when it's calm, it's the same basic principle.