lo Journal of Agricultural Research voi. iv. no. i 



OTHER PLANTS EXPOSED TO INFECTION OF THE FUNGUS 



A number of experiments were made in order to test the pathogenicity 

 of the Phoma fungus upon eggplant, potato, sugar beet, Jimson weed, 

 garden pea, bean, and pepper plants. 



Eggplant {Solanum melongena) . — In February, 191 4, young egg- 

 plants growing in pots at the greenhouse were sprayed with a spore 

 suspension of the Phoma fungus made from a 4-weeks-old corn-meal 

 culture. Some of the sprayed plants were placed beneath glass bell jars, 

 with cotton-plugged tops, and some were placed in a glass infection cage. 

 Control plants were used in both cases. The bell jars were removed from 

 a few of the plants after 48 hours, but were kept over others for a period 

 of 10 days. At the end of this time numerous small brown spots had 

 appeared on the leaves of the plants kept beneath the bell jars and upon 

 the plants in the infection cage, but no spotting was found upon plants 

 uncovered after 48 hours. Lower leaves of the diseased plants were 

 yellowish and drooping and were the first to show the spotting. Tissue 

 from these spots was examined with the microscope, and pycnidia and 

 spores observ^ed. Spores could be seen issuing from the pycnidia in 

 long coils. The majority of spots remained small in size, only a few 

 becoming 3 to 8 mm. in diameter. The spotted leaves did not fall from 

 the stems, and the inoculated plants continued to grow and to produce 

 new leaves. By means of agar plates the Phoma fungus was recovered 

 from spotted tissue taken from plants kept under bell jars and from 

 sprayed plants in the infection cage. Control plants kept under similar 

 conditions of temperature and moisture showed no spotting. From these 

 experiments it appears that the Phoma isolated from diseased tomato 

 tissue is slightly pathogenic to eggplant,^ but since spotting occurred only 

 upon plants kept beneath bell jars or within the infection cage for several 

 days, it is not probable that eggplants grown under ordinary conditions 

 of temperature and moisture would become infected with this fungus. 



Potato plants {Solanum tuberosum) . — Healthy young potato ^ plants 

 15 to 20 cm. high, growing in pots at the greenhouse, were sprayed on 

 January 28, 191 4, with a spore suspension of the Phoma fungus made 

 from a 2-weeks-old corn-meal culture. Some of the plants were covered 

 with bell jars, while others were placed in an infection cage. The bell jars 

 were removed from some of the plants after 48 hours, but were kept over 

 others for a period of 10 days. Within six days discolored spots were 

 noticed upon leaves of plants under the bell jars and upon leaves of 

 those in the infection cages (PI. B, fig. i). The lowest leaves showed the 



I Cultures of the Phoma were compared with Phomopsis vexans (Sacc. and Syd. ) Harter, recently described 

 by L. L. Harter (1914) as causing fruit-rot, leaf-spot, and stem-blight of eggplant. The two fungi were 

 found to be quite distinct morphologically, and according to inoculations made by Harter Phomopsis 

 vexans is not parasitic on tomato. 



^Saccardo reports the following species of Phoma on Solanum tuberosum: "Phoma nebulosa (Pers.) 

 Mont." (1884, p. 135); "Phoma eupyrena" (1884, p. 127); "Phoma solani Cooke et Hark." (1893, p. 17s); 

 "Phoma solanicola Prillieux et Delacroix" (1892, p. 175). 



