. Fungous diseases of plants, with chapters on physiology, culture methods and technique . iafor a more profuse mycelial development. Moreover, on solidmedia mature pycnidia may be secured within a few weeks. Theydevelop superficially, and are then composed of loosely wovenbrown hyphae. The mycelium is entirely distinct from that ofCercospora Apii. Control. In the field Bordeaux or ammoniacal copper carbo-nate may be used as a spray, but in the storage cellar it is necessar)*to pay special attention to all matters of sanitation. When thedisease is abundant in the field, additional risk is take
. Fungous diseases of plants, with chapters on physiology, culture methods and technique . iafor a more profuse mycelial development. Moreover, on solidmedia mature pycnidia may be secured within a few weeks. Theydevelop superficially, and are then composed of loosely wovenbrown hyphae. The mycelium is entirely distinct from that ofCercospora Apii. Control. In the field Bordeaux or ammoniacal copper carbo-nate may be used as a spray, but in the storage cellar it is necessar)*to pay special attention to all matters of sanitation. When thedisease is abundant in the field, additional risk is taken, of course,by placing the crop in storage. 362 FUNGOUS DISEASES OF PLANTS LI. SEPTORIA: OTHER SPECIES Septoria Lycopersici Speg., leaf blight of the tomato. The tomato is attacked by several leaf fungi which may become destruc-tive, and of these fungi the one most injurious throughout therange of tomato culture is the organism causing what is known asleaf blight. The leaves are the parts most severely affected, and onthese parts appear numerous small angular spots pale in the centers. Fig. 180. Tomatoes defoliated by the Leaf Blight Fungus(Photograph by H. H. Whetzel) and with colored borders. The affected leaves have a tendency tocurl dorsally throughout their length, eventually drying and and twigs may also be affected, and small, elongate, darkspots may appear on the fruit. The pycnidia are found on the upper surfaces of the leaves inthe larger spots. It is probable that the fungus passes the winterin the old leaves and other refuse. The use of Brrdeaux mixture during the early part of theseason has generally resulted in successful prevention. FUNGI IMPERFECTl 3^3 h Septoria Ribis Desm.^ is common upon various species of respect to the economic hosts many varieties of both currantsand gooseberries are subject to attack. Large spots with palecenters and brown borders are produced (Fig. i8i). These arereadily distinguished from those produced by t
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