23 2 Nebraska State Horticultural Society. 



No one has yet made an exhaustive investigation of the disease, 

 although Dr. Heald examined a number of the diseases pines, sent from 

 the reserve, last year, and found a fungus of the germs Cladosporium 

 to be present. He thinks that this fungus is the cause of the disease, 

 but has made no inoculation, and therefore can not say positively that 

 Cladosporium is the cause. 



An examination;^ of a number of specimens sent from Halsey this 

 spring shows that riadosporium and also a species of Pestalozzia is 

 present. The surface of the dead portions of the needles is marked by 

 numerous dark patches, which upon close examination, prove to be 

 masses of fungus threads bursting through the epidermis. A cross 

 section of the mycelium reveals the presence of a dark brown 

 mycelium lying right beneath the epidermis. This mycelium has a 

 close resemblance to that of Cladosi>orium in its advanced stage, but 

 since no spores could be found, the fungus could not be positively de- 

 termined to be Cladosporium. In a plate culture, made by placing bits 

 of the above mycelium into a medium of aqua with 155 per cent glucose, 

 colonies of Cladosporium were obtained, together with several other 

 fungi. *In this case spores were produced, so that Cladosporium was 

 identified beyond any doubt. Spores of Pestalozzia were obtained by 

 placing dead needles in a moist chamber, but no Pestalozzia was found 

 in the plate culture. 



From present indications Cladosporium seems to be the cause of 

 the disease, but since at lesat two fungi which are known to attack 

 pine seedlings are found to be present, namely, Cladosporium and 

 Pestalozzia, the only way of determining positively which one is caus- 

 ing the trouble is to secure spores from pure cultures of both fungi, 

 and make inoculations of healthy young pines. 



A number of normal one-year-old Bull Pines and Jack Pines were 

 recently secured from the reserve at Halsey, and planted out of doors 

 under a shade frame. Several Bull Pines were inoculated with 

 Pestalozzia by placing the spores in ordinary hydrant water and apply- 

 ing to the seedlings with an atomizer. A number of the needles on 

 several seedlings were injured in order to expose fresh tissues, while 

 the other seedlings were left in their natural state. All of the inoculated 

 seedlings were covered with bell jars in order to secure favorable con- 

 ditions for the germination of the spores. Since these inoculations were 

 made on June 2, or only five days ago, sufficient time has not yet elapsed 

 to secure any results. 



Pure cultures of Cladosporiums have not yet been obtained, and 

 therefore no inoculations have yet been made with this fungus. 



