<P> De Bary published his first work on fungi in 1861, and then spent more than 15 years studying Peronosporeae, particularly Phytophthora infestans (formerly Peronospora infestans) and Cystopus (Albugo), parasites of potato . In his published work in 1863 entitled "Recherches sur le developpement de quelques champignons parasites", he reported having inoculated spores of P. infestans on healthy potato leaves and observed the penetration of the leaf and the subsequent growth of the mycelium that affected the tissue, the formation of conidia, and the appearance of the characteristic black spots of the potato blight . He also did similar experiments on potato stalks and tubers . He watched conidia in the soil and their infection of the tubers, observing that mycelium could survive the cold winter in the tubers . From all these studies, he concluded that organisms could not be generated spontaneously . </P> <P> He did a thorough investigation on Puccinia graminis, the pathogen of rust of wheat, rye and other grains . He noticed that P. graminis produced reddish summer spores called "urediospores", and dark winter spores called "teleutospores". He inoculated sporidia from the winter spores of the wheat rust on the leaves of the "common barberry" (Berberis vulgaris). The sporidia germinated and led to the formation of aecia with yellow spores, the familiar symptoms of infection on the barberry . De Bary then inoculated aecidiospores on moisture - retaining slides and then transferred them to the leaves of seedling of rye plants . In time, he observed the reddish summer spores appearing in the leaves . The sporidia from the winter spores germinated, but only on barberry . De Bary clearly demonstrated that P. graminis required different hosts during the different stages of its development (a phenomenon he called "heteroecism" in contrast to "autoecism", when development takes place only in one host). De Bary's discovery explained why the eradication of the barberry plants had long been practiced as a control for rust . </P> <P> De Bary also studied the formation of lichens which are the result of an association between a fungus and an alga . He traced the stages through which they grew and reproduced and the adaptations that enabled them to survive drought and winter . He coined the word "symbiosis" in 1879 in his monograph "Die Erscheinung der Symbiose" (Strasbourg, 1879) as "the living together of unlike organisms". He carefully studied the morphology of molds, yeasts, and fungi and basically established mycology as an independent science . </P> <P> De Bary's concept and methods had a great impact on the growing field of bacteriology and botany . He published more than 100 research papers and influenced many students who later became distinguished botanists and microbiologists such as Sergei Winogradsky (1856--1953), William Gilson Farlow (1844--1919), and Pierre - Marie - Alexis Millardet (1838--1902). He was one of the most influential of the 19th century bioscientists . De Bary died of a tumor of the jaw, having undergone extensive surgery, on January 19, 1888 in Strasburg . </P>

Who wrote the book fungi and disease in plant