The Hessayon books are dated it's true, but I'd still buy a copy as often they're the only books with pictures of the pests and diseases that you might come across. OK so he usually recommends nuking them, but once you've identified what you've got you can then refer to an organic book to discover how to beat them naturally. Most books usually make do with a written description of pests which, when many look very similar, is not always enough.