Hostas are fed on by grasshoppers who make large irreular holes in leaves. Use carbaryl in the morning. They are fed on by black vine weevils (night feeders) which eator make paper punch size holes in leaf margins. Use carbaryl at dusk. And they are fed upon by slugs. No insecticide. Slugs like hostas that are well watered and mulched. Cut back on watering. If not watering - get rid of mulch.
As for tomatoes, there are two diseasesthat cause these symptoms - early blight and septoria. Use a recommended protective fungicide for your state and start right after you plant. Treat every 7 to 14 days depending on how wet the foliage stays. Stop at least two weeks before picking and eating the tomatoes. Disease will probably still attack plants but the sprays reduce how soon the plant defoliates.