1921] COOK—PEACH YELLOWS AND LITTLE PEACH 251 
structure did not show any differences of importance, and will not 
receive further consideration at this time. The study, however, of 
the amount and location of the starch within the tissues of the 
leaves and green shoots gave some interesting data, and therefore 
the basis of the work is a comparative study of the results of 
photosynthesis and translocation of fob a Gangs in healthy and . 
diseased trees. 
Before considering this phase of the hak the generally recog- 
nized symptoms of these diseases are indicated, since they must be 
referred to from time to time. The first symptom in both cases is 
an infolding along the midrib or rolling of the margins, accompanied 
by a pronounced backward curving from base to tip so as to give 
&, Sickle or crescent effect, and the development of a decidedly 
leathery texture which is very apparent to the touch. The second 
symptom for yellows is the development of enlarged, prematurely 
ripened fruits, which show a characteristic red spotting or blotching 
over the surface and through the flesh, especially prominent near 
the stone. The final stage in the yellows is the development of 
fascicled, willowy shoots. Very similar symptoms may be pro- 
duced by partial or complete girdling of trunk or branch by winter 
injury at the collar, by borers, by label wires, or other factors. 
There is no doubt that many of the reported cases of peach yellows 
in the past were in reality cases in which the symptoms were 
produced by some of these causes. ‘The first stage or leaf characters 
in little peach is similar to that of yellows, but is very likely to be 
more pronounced than in yellows. In the second stage the fruit 
is small and ripens later than in the normal healthy trees. There 
is no willowy growth as in the case of yellows. The symptoms 
just described are subject to many variations, dependent upon 
cultivation, care, and other factors. Yellow foliage may be due 
to many other causes, and is not necessarily a symptom of yellows, 
In fact, trees infected with this disease may be very green, especially 
if fed with a fertilizer high in nitrogen. Trees infected with yellows 
will sometimes persist for a number of years, but those infected 
with little peach usually die in a comparatively short time. 
In a normal healthy plant the starch content is expected to be 
much greater in the afternoon than in the early morning, due to 
