Apr. 15, i9i8 A Lcafblight of Kalmia lafifolia 201 



From water suspensions of these spores corn-meal agar and beef -agar 

 plates were made for the purpose of starting single-spore cultures. 

 Under the microscope single spores were marked and, when germination 

 had started, were transferred to corn-meal agar slants and potato cylin- 

 ders. These transfers were used for the greater part of the inoculation 



experiments. 



INOCULATION EXPERIMENTS 



INOCULATIONS INTO KALMIA LATIFOLIA 



The first inoculation tests were made on July 17, 1914, on twigs of 

 Kalmia latifolia, which were broken off and placed in beakers and kept 

 on a laboratory table. A suspension of the spores (from cirri extruded 

 from pycnidia in corn-meal cultures 5 weeks old) was made in sterile 

 water, and the leaves were sprayed on both sides with this suspension, 

 and then placed under bell jars for three to four days. Some of the 

 leaves which had been pricked with a sterile needle were held as controls. 

 All of the leaves which had been pricked when inoculated showed signs 

 of infection at the end of 11 to 15 days. The disease, however, did not 

 progress rapidly, being confined to tiny brown spots scattered irregularly 

 about over the leaf blade. This was undoubtedly due to the fact that the 

 air in the laboratory was too dry for a rapid spread of the infection. 

 The spots were typical of those observed on the original material, and 

 cross Sections showed the presence of the same delicate mycelium in 

 the leaf tissues. Plates were poured, and pure cultures of the fungus 

 inoculated were obtained. 



On November 4, 1914, 12 plants of K. latifolia were inoculated by 

 spraying on suspension of the spores from cultures 5 weeks old. Needle 

 pricks were made in about half of the leaves inoculated. The plants 

 were kept in the greenhouse under inoculating cages. On the same day 

 six branches from a very large plant of K. latifolia were broken off, and 

 placed in bottles standing in water, over which bell jars were placed, 

 and kept in the laboratory after inoculation. Some of them were inocu- 

 lated simply by smearing moistened spores over the leaf surfaces, but 

 the majority were sprayed with the suspension of spores, after which 

 needle pricks were made. 



Two plants were inoculated by spraying with spores from a fungus 

 belonging to the genus Phyllosticta, w^hich had developed in the damp- 

 chamber incubation. One other plant was inoculated by placing on both 

 leaf surfaces spores of Alternaria sp., which had developed also in the 

 damp chamber, and one was inoculated with spores of Pestalozzia sp., 

 needle pricks having been made in both cases. 



Two plants were sprayed with sterile water, pricked v/ith sterile needles, 

 then placed under bell jars, and kept as controls. 



I«n this experiment the laurel plants v/ere kept under the bell jars for 

 21 days, and during this time several new leaves had started; but the 



