444 DISEASES OF CULTIVATED PLANTS 



Hall, Dr. C. J. J, van, and Drost, A. W., Soc. Bot. Neer- 

 landaise, 4, p. 243 (1908). 



Massee, Bull. Misc. Inform. , Trinidad (1901). 

 Ritzema Bos, Tijdschr. Plantenzeik. (1900), p. 65. 



Fig anthracnose. A disease of figs has been observed in 

 Carolina, caused by Colletotrichum carica (Stevens and Hall). 

 The fruit is attacked in various stages of growth, and shows 

 large blotches covered with the fruit of the fungus. The 

 leaves are also attacked. 



Spore-mass brown, then black; bristles few sometimes 

 none slender, brown; conidia elongated, 8*5-20 X3'5-6 p. 



Stevens and Hall, Zeit. Pflanzenkr.^ 19, p. 65 (1909). 



Bitter orange spot. The leaves, twigs, and fruit of the 

 bitter orange or pomelo suffer in Florida from injury caused 

 by Colletotrichum gloeosporioides (Hume). Irregular brownish- 

 yellow spots appear on the leaves, and at a later stage these 

 spots on the upper surface of the leaf are marked with black 

 points arranged in conce'ntric circles ; these represent the 

 fruit of the fungus. The young twigs are also attacked, the 

 spores probably gaining an entrance through wounds. 



Spores cylindrical, hyaline, continuous, 16-18x4-6 \i. 



Hume, H. H., Florida Agric. Exp. St. , BulL No. 74 (1904). 



Sisal hemp disease {Colletotrichum agaves ; Sacc.) causes 

 considerable injury to sisal hemp and cultivated agaves. 

 The older leaves are attacked first, small sunken patches 

 occurring at the points of infection ; these points gradually 

 extend. Sisal hemp leaves wither from just under the ter- 

 minal spine for half their length or more. 



Pustules conical, formed under the epidermis on pallid 

 spots; bristles few, brownish-yellow, 2-3-septate, go-iooX 

 5-6 '/*';" conidia straight, hyaline, 22-26x4-5 /*. 



Cutting off the leaves on the first appearance of the disease 

 is the only practicable means of checking the spread of the 

 fungus. 



Hollyhock anthracnose (Colletotrichum althaeae, Southw.) 

 causes trouble to hollyhocks grown in greenhouses in the 

 United States. Any part of the plant may be attacked ; on 

 the leaves brown spots are formed which may increase in size 

 until the entire leaf is diseased and withered. Spots light 

 yellowish-brown to black. 



