192 Keport op the Botanist of the 



become yellow; but tbe imtbrifty condition brougbt about by 

 such causes should be carefully distinguished from the genuine 

 yellows. The most reliable symptoms of yellows are premature 

 ripening of the fruit and the occurrence of red streaks in the 

 flesh of the fruit. 



Brown Spot {Helminniosporium carpopliilum L^v.). — During the 

 past two years we have frequently seen peach fruits affected 

 with a fungous disease called brown spot. It begins its attack 

 while the fruit is still green, but is most conspicuous on the ripe 

 fruit where it apears in the form of pink spots and cinnamon- 

 brown areas. At first the spots are no larger than a piuhead 

 and have a brilliant pink color such as the San Jos6 scale insect 

 produces on apples and pears. In the center of the pink spot 

 there is usually a circular, brown or fawn-colored portion. At 

 this stage the spots are often slightly elevated. In time, the 

 spots coalesce to form irregular areas of cinnamon-brown color 

 and then the pink discoloration of the fruit mostly disappears. 

 Such areas may occupy from one-fifth to one-half of the surface 

 of the fruit and, according to our observations, occur exclusively 

 upon the upper surface. (See Plate XXV, Fig. 2.) 



Ordinarily no spores are found in the younger spots, but on 

 the older, brown areas the spores of an Helminth osporimn occur 

 sparingly. The spores are light brown and mostly 2- to 3-septate 

 although 4- to 6-septate spores are not uncommon. In almost 

 any microscopic preparation containing scrapings from the 

 brown areas there may be found a few of the Hclminthosporiinn 

 spores, but they are never abundant. There is little doubt that 

 these spores belong to the fungus which causes the brown areas, 

 and that the fungus is Helmintliosporium carpopliilum-'' Lev. 



What seems to be the same fungus^" has been found on peach 

 branches. Conspicuous enlargements resembling the black knot 

 of plum frequently occur on peach branches in this State. (See 



=°Accordmg to Adcrliold {CentralltJatt f. Bakt., Parasitcnk. n. Infektionskr., 

 II, 5 : 523.) llchnintJiospoyiiim carpopliilum Lev, is a synouj-m of ClaS' 

 tcrosporiiim amygdalearum Sacc. 



"The fungus grows readily on the ordinary culture media. The spores 

 germinate freely in tap water and in distilled water; but in the latter med- 



