October, ’23] 
turner: kernel spot on pecan 
441 
they commence to darken and in time become very dark brown in color. 
This discoloration may also extend beyond the limit of the actual “spots” 
in severe cases. A horizontal section of the spot is almost a semicircle, 
the diameter being the surface of the kernel, showing that the spot is 
actually a more or less perfect hemisphere. This hemisphere is very 
distinct in that, at an early stage, it is outlined in brown, and later the 
entire affected area becomes discolored. An examination of the spot, 
in section, shows that the cells are all collapsed, giving a gross appearance 
of sponginess. One other characteristic is that a majority of the spots 
occur on the ridges of the kernels; i. e.', on the portion nearest the shell. 
At first the affection seems to have no effect upon the flavor of the nut but 
after a short time the spot itself becomes bitter and this bitterness is 
finally imparted to the entire kernel. 
Kernel spot usually affects only those varieties which have the thinnest 
shells, and plump meats. Thus Schley and Curtis nuts are frequently 
attacked very severely, as much as 50% of their crop being ruined, while 
such varieties as the Stuart (thick shell) and Fiotcher (non-plump meat) 
will escape injury, though growing next to the susceptible varieties. 
The trouble is of very serious importance to the growers of pecans. 
True it occurs only in slight amounts during most years but occasionally 
as in 1916 and 1921, in Georgia, fully a quarter of the crop is affected in 
many groves. Furthermore the losses are particularly severe in that no 
indication of the trouble can be seen until the nuts are cracked. As a 
consequence quantities of nuts are shipped in perfect good faith by 
the growers and pass thru the channels of trade until they reach the final 
consumer. The finding of spoiled nuts immediately reacts thru retailer 
and wholesaler to the grower and in most cases the latter is obliged to 
recall his product. Thus there is a loss not only of the crop itself but 
of the freight both ways and the good will of the public. Had the grower 
known of the trouble in the beginning the nuts could have been sold, at 
reduced prices to be sure, to the crackeries. 
Very little has been published concerning kernel spot. This is prob¬ 
ably due to the fact that the trouble has not been a major one every year. 
Rand first gave the trouble some attention. 1 He stated that kernel spot 
was a fungus disease and isolated a fungus, Coniothyrium caryogenum 
Rand, which he pronounced to be the causative agent. 
In 1916 the writer observed what appeared to be a correlation between 
kernel spot and the use of cow peas as a summer cover crop. Several 
*Rand, Frederick V., 1914. Some diseases of pecans. In four, of Agr. Res., 
Vol. 4. pp. 303-338. 
