The plant-pathogenic powdery mildews, characterised by growing on the external surfaces of plants. This Order contains six genera defined by the cleistothecia, which may have one or several asci, and various types of appendage: Erysiphe (several asci, simple appendages), Sphaerotheca (one ascus, simple appendages), Microsphaera (several asci, dichotomous appendages), Podosphaera (one ascus, dichotomous appendages), Phyllactinia (several asci, rigid appendages), and Uncinula (several asci and curled appendages). The imperfect stage, consisting of hyphae and conidia only, is called Oidium. Erysiphe

A genus of the Erysiphales, or powdery mildews. The most important species are Erysiphe graminis, which attacks wheat, barley, rye, oats, and many fodder grasses; Erysiphe polygoni, which attacks peas, clovers, and swedes; and Erysiphe cichoracearum, which has a wide host range that includes various cucurbits, tobacco, and many ornamentals. vertical resistance are common and there is considerable scope for breeding for horizontal resistance by amateurs.

Growing Soilless

Growing Soilless

This is an easy-to-follow, step-by-step guide to growing organic, healthy vegetable, herbs and house plants without soil. Clearly illustrated with black and white line drawings, the book covers every aspect of home hydroponic gardening.

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