Yes, I spray the tops and bottoms. The best thing for the ground as well as your plants, is to make sure you have good soil with nutrients.
Healthy plants don’t happen with out great soil-Compost, nutrients, and roatation planting help to achieve this.
Reading my first organic gardening book, I remember the author talking about when he first started out gardening. He noticed that the plants that were in an overlap area were under performers. This made him a believer in rotation planting.
Hubby has used burning, solarization under black plastic, and fungicides on one of his gardens, but so far, I have not had to do anything drastic with mine.