Neem oil is a broad spectrum pesticide which acts as an insecticide, fungicide, and miticide.  As fungicides, they are most effective when used as a preventive or when disease pressure is light.  Neem works by coating plant surfaces, therefore preventing fungal spore germination and killing external fungi on leaf surfaces.  Through coverage is important.  As an insecticide/miticide, use when insect/mite pressure is light to moderate.  Neem suffocates insects and mites on contact and is especially effective on whiteflies, aphids and other soft bodied insects. It also acts as a repellent.  Since tis product is an oil, it can also kill bees if they are exposed to direct treatment so we recommend applying this product when they are not visiting your plants.  Late evenings are the best time to spray.