. Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. disease is distinguished from the leaf spot by smaller spots more colored when young and more nearly circular. They are also less clearly defined on the under surfaces. The blight also attacks the fruit. In this case the spots are at first red but later darker in color. The drying of the surface layers accom- panying the effects of this disease may cause a cracking very much as in the case of pear scab. The fungus. The larger spots of the leaf blight will generally show at the time
. Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. disease is distinguished from the leaf spot by smaller spots more colored when young and more nearly circular. They are also less clearly defined on the under surfaces. The blight also attacks the fruit. In this case the spots are at first red but later darker in color. The drying of the surface layers accom- panying the effects of this disease may cause a cracking very much as in the case of pear scab. The fungus. The larger spots of the leaf blight will generally show at the time of leaf fall one dark papilla in the center of each. This papilla is an indication of an acervulus, or spore-producing stroma. The mycelium from which this stroma originates penetrates the epidermal layer and also to some extent the hypodermal tis- sues, and the affected region shows a general collapse of the cells. From the subcuticular stroma there are produced on minute conidiophores numerous "insect-like" spores (Figs. 185, 186). The spores germinate readily and the fungus is thereby spread during the same season. Various authors have described what is supposed to be a perfect stage of this fungus. Sorauer1 has referred the ascogenous stage to Stigmatea Mespili. Atkinson 2 has found this fungus on wintered leaves of the quince and has considered it to be a member of the genus Fabraea. Control. Experiments upon nursery stock have shown that Bordeaux mixture of any standard strength may be used success- 1 Pflanzenkrankheiten, /. c. (cf. p. 371). 2 Garden and Forest 10 : 73-74. 1897. Fig. 184. Entomosporium on Quince. (Photograph by H. H. Whetzel). Fig. 185. Entomosporium maculatum. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Duggar, Benjamin M. (Benjamin Minge), 1872-1956. Boston ; New York
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