One very good product for controlling various pests and diseases, and which is suitable for organic gowers is SB Plant Invigorator.
Controls a wide range of important pest species including Whitefly, Aphid, Spider Mite, Mealybug, Scale and Psyllid. Due to the physical mode of action these pests will not become resistant to SBPI. For use on all edible and ornamental crops
Used by professional and amateur growers and gardeners worldwide. It also controls powdery mildew on courgettes and peas and some fungal infections on brassicas
SBPI has a “physical mode of action”.
There is no harvest interval after applying SBPI.