KERNEL-SPOT OF THE PECAN AND ITS CAUSE. 6 
was of a serious economic importance in southern Georgia in 1916 
and again in 1921. Some growers in northeastern Florida reported 
an entire loss of their Curtis nuts in 1919 and 1920, but these same 
Florida growers reported the loss to be slight in 1921. 
DESCRIPTION OF KERNEL-SPOT. 
The spots are found only upon the kernels of the pecan nuts. Ordi- 
narily no evidence of the trouble is apparent until the shell is 
removed. The writer has observed that when nuts are punctured by 
the Xezara before or soon after the nuts have attained their full 
growth small sunken places will be formed in the shucks of the 
nuts. (Fig. 1.) 
Punctures may also be seen in the shell if an examination is made 
while the nut is' yet green. The pecan shell is greenish white until 
the maturing processes start, and 
during this stage punctures appear 
as small brown spots less than 1 
millimeter in diameter. These spots 
can be followed through the shell 
by shaving or scraping with a 
knife, and a typical spot will 
usually be found on the kernel 
immediately beneath it. These FlG 1# _ A pecan nut of the Curtis 
Spots are not evident On the Shell variety, showing indentations caused 
after the nuts have matured and h} 7 early P unctures of Ne * ara vir ^ 
developed the nut-brown color. 
The centers of the spots are always found upon the ridges or the 
edge of the pecan kernels, and never in the creases or on the inside 
surface of the halves of the kernel. (Fig. 2.) 
In almost all typical kernel-spots one w T ill find a small papilla, or 
pimplelike structure, in approximately the center of the spot. A 
magnified cross section of a spot through this pimplelike structure 
shows the epidermal cells and those cells lying immediately beneath 
this point as being ruptured. (Fig. 3.) Undoubtedly this small 
elevated place marks the point of entrance of the seta of the insect. 
The kernel spots are usually but not always sunken below the surface 
of the adjacent healthy tissues. They vary in size from 2 to 5 mil- 
limeters in diameter. 
In color, the surface of the spots ranges from brown to black. In- 
ternally the affected tissues extend in approximate hemisphere be- 
neath the surface and are frequently separated from the healthy tis- 
sues by a distinct brown layer. The internal part of the spots is 
almost white, pithy and porous, and apparently is not discolored or 
disorganized until organisms of decomposition gain admittance. The 
spots are decidedly bitter, but this bitter taste is not imparted to 
the unaffected portions of the kernel. 
