The crop duster flies low over fields, so tradition reads it as close, practical care for what you are growing. Dream books also see it as something spread widely over your life, nourishing or unwanted depending on the mood of the dream.
Has this come up in your dreams before? What was going on in your life then?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.