422 REPORT OF STATE BOARD OF HORTICULTURE. 



and do not know that it occurs, although it is possible that the excessive 

 blighting in the spring of 1896, which was attributed to the unusual rainfall, 

 may have been due to Monilia. which would certainly have flourished under 

 conditions which then prevailed. 



BLIGHTING OF TWIGS. 



In the peach, the blossoms of which have very short pedicles, the blight 

 does not stop with the destruction of the flower, but the mycelium of the 

 fungus may extend through the pedicle into the tissues of the twig. The 

 portion of the twig thus attacked soon assumes the charactertistic leathery 

 brown color of brown rot. The extent of the tissue thus involved usually 

 varies with the conditions of heat and moisture, but should it extend around 

 the twig so that the latter is girdled, all of the terminal portion beyond the 

 point of infection will blight. This twig blight of the peach occurs not 

 only in spring when the mycelium enters the twig through the pedicles of 

 the blighted blossoms, but it also occurs in fall, when it enters through the 

 pedicles of rotting peaches, which have been allowed to remain on the trees. 

 This twig blight of the peach, which is due to Monilia, should be distin- 

 guished from the blight which occurs in spring as a result of the attacks of 

 the larvae of the peach-twig borer, which is occasionally quite general. 

 Blight of prune twigs is frequently caused by this insect, but I have never 

 observed it to result from an attack of Monilm. 



ROTTING OF THE FRUIT. 



The appearance of brown rot u^Don the fruit varies somewhat with the 

 variety attacked. On chei'ries and peaches a small circular brown spot ap- 

 pears at the point of infection, and this rajjidly spreads until the whole fruit 

 becomes shrunken, soft and discolored. As the disease spreads the surface 

 of the diseased tissues becomes covered with the characteristic ash-gray 

 conidial tufts. In apples, pears, and quinces the disease spreads in much 

 the same way, but more slowly, and usually with less abundant spore forma- 

 tion. In prunes the disease may effect the entire fruit and still produce but 

 little external evidence of its presence. Prunes appai^ently sound, when 

 opened may exhibit a brownish rotten appearance due to the work of the 

 fungus. We have seen many bushels of prunes taken into the warehouse at 

 night in an apparently healthy condition, which the following morning were 

 well covered with the conidial tufts of Monilia, and many of these prunes 

 which did not show such tufts and were placed in the drier under the im- 

 pression that they were in good condition, failed to produce a good quality 

 of dried fruit. About the first external evidence of brown rot in the Italian 

 prune is the presence of the conidial tufts, and these do not develop freely 

 unless in a warm, moist atmosphere. 



BROWN ROT AND ORCHARD CONDITIONS. 



We have hitherto considered brown rot largely from the laboratory 

 standpoint. Let us now examine the same facts in their relations to orchard 

 conditions. 



