40 A PLANT-DISEASE SURVEY IX TEXAS. 



Root-rot {RMzoctonia sp.). — The plants which are affected remain 

 dwarfed for a time and then wilt and die. The stems up to the 

 ground level and a little above are sunken and have little wartlike 

 nodules. The loss was quite serious in an irrigated garden where it 

 was observed. 



Specimen collected : San Antonio. 1329. 



GLOBE ARTICHOKE. 



Leaf-spot (Oercospora obscura Heald and TTolf. 32). — The pres- 

 ence of this disease on the globe artichoke (Oynara scolyrmis L.) 



is made manifest by the circular gray spots, varying in diameter 

 from 1 to -2 mm., which appear on the upper surface of the leaf in 

 great numbers. Each spot has a faint brown border, with the tufts 

 of conidiophores on the upper surface. Since the lower surface of 

 the leaf is covered by a silvery tomentum the spots appear as slightly 

 darker areas. 



The conidiophores are in groups of from four to seven, epiphyl- 

 louSj nonseptate. varying in length from 50 to Q p, and in width 

 from -i to 5 fj.. brown, with a hyaline tip. The conidia are cylin- 

 drical in shape. 40 to 74 by 3 to 4 p, three to four septate, dilutedly 

 colored, and straight or curved. (PI. III. fig. 6.) 



Specimen collected: Beeville. 1S61 (type specimen). 



^rUSKMELON. 



Anthracnose {Collet otrichum lagenarium (Pass.) Ell. and Hals). — 

 The appearance of large, dead, brown patches on the leaf of the musk- 

 melon (Cucumis melo L.) marks the presence of this fungus. 



Specimen collected : Beeville. 1827. 



leaf -blight (Alternaria brassicae (B.) Sacc. var. mgrescem 

 Pegl. ) . — Large brown spots are formed on the foliage, attaining 1 cm. 

 in diameter. "When numerous the leaves turn brown and curl. It 

 was observed to be sufficiently abundant in one field to cause a very 

 serious loss, and has been reported to be a very destructive blight 

 south of our territory. 



Specimens collected : Austin. 1425. 3136 : Hallettsville, 2904. 



Hoot-knot (Heterodera radicicola (Greefj Mill.). — This trouble 



was observed in an irrigated garden where the plants remained 

 stunted for a time, and at length succumbed. The crop was an 

 entire loss. (PI. IX. fig. 2.) 



Specimens collected : San Antonio. 1327 : Austin. 3135. 

 226 



