202 Journal of Agricultural Research voI.xiii.no.s 



disease progressed so rapidly owing to the very moist conditions that it 

 soon reached these new leaves through the stem, when they promptly 

 blighted. No disease appeared in the controls. 



Those plants left under the cages in the greenhouse showed the first 

 signs of the disease on November i8 in the form of numerous, small, 

 brown spots on the upper surfaces of the leaves. On account of the moist 

 air of the inoculating chambers, these spots soon coalesced, forming the 

 typical brown, brittle areas (PI. 14, A). On December i every plant 

 and branch inoculated with the fungus was badly diseased; in fact, 

 practically all of the leaves had either fallen or become brown, dry, and 

 brittle. The stems in each case were also infected. Poured plates were 

 made from these inoculated plants, and the fungus inoculated was 

 isolated in pure culture from each of the inoculated plants. 



The two plants inoculated with the spores of Phyllosticta sp. gave no 

 positive results; nor did those inoculated with Alternaria sp. and 

 Pestalozzia sp. The controls, both at the greenhouse and laboratory, 

 remained healthy. 



In the manner thus outlined inoculation experiments were conducted 

 from time to time during a period of three years, inoculating in all about 

 50 plants of K. latifolia and several dozen cut branches, most of which 

 gave positive results. One interesting fact observed in this connection 

 was the effect of keeping the cut branches or plants under very moist 

 conditions under bell jars. In many cases stimulation of growth resulted, 

 and practically no injury was noticeable in any plant or branch. In one 

 experiment (March 4, 191 5) one of the control plants was allowed to 

 remain standing in a very moist atmosphere under a bell jar from March 4 

 until April 14, when it showed several new leaves and appeared to be 

 perfectly healthy. One of the leaf-inoculated plants was also left for 

 this same length of time, when it showed on the stem the typical pycnidia 

 from whch the yellow cirri were extruding (PI. 15, B). 



On January 7, 1916, experiments were started to determine whether 

 stomatal infections are possible under ordinary conditions. One plant 

 out of six inoculated on this date by smearing moistened spores on the 

 uninjured low^er surface of the leaves showed typical diseased areas. 

 However, this one experiment is not considered of much value, as the 

 infection may have started through some injury too small to be seen at 

 the time of inoculation. A microscopic examination of numerous 

 sections failed to show hyphas penetrating the stomata. The leaves 

 inoculated on this plant were new ones, and very delicate, and it can be 

 readily seen that even handling them might result in minute injuries 

 through which the hyphse might enter. 



The experiments conducted as just described seem to afford sufficient 

 evidence as to the pathogenicity of the fungus isolated. It is a wound 

 parasite, or at least not an exceedingly active parasite. However, 

 once it gains entrance to the parenchyma of the plant it will kill li\nng 

 tissue and may involve entire branches or even the whole plant. 



