Copper is my Secret Weapon for fungal/blight issues on just about anything. AlgoFlash is my go-to fertilizer for just about everything, and a Bloom Booster (Miracle Grow) for hanging baskets, porch pots and in-ground flowers.
Also, make sure tomatoes and peppers and eggplant and zukes & cukes have good spacing; crowding results in poor air circulation and sets the stage for disease later in the season.
I have tomatoes spaced 18” by 24” and will be trained to an 8’ wire mesh. Question is to trim secondary stems or not. Or just trim lower (3’) ones for ventilation and then let upper ones produce more flowers/fruit?
Is there some “best way” for humid summers?