58 BULLETIN 1474, U. S. DEPARTMENT OF AGRICULTURE 
insufficient lime in the Bordeaux mixture. Spray burn of the fruit 
of the orange has rarely occurred on the experimental plots except 
where an excessive number of applications were made, and in only 
a few instances has it been reported by commercial growers. 
Although occurring in small proportions, a peculiar type of rind 
blemish developed on the oranges that received many applications 
of Bordeaux-oil emulsion (pi. 6, D), and it was not observed on 
unsprayed fruit. This has been observed several times and is con- 
sidered to be spray injury. It has not been observed on grapefruit. 
The excessively sprayed oranges colored up about two weeks earlier 
than the unsprayed checks, and they also took on a deep orange, 
almost tangerine, color ; the taste became insipid, the rind coarse and 
puffy ; creasing developed before Christmas ; and the fruit dried out 
three or four weeks in advance of unsprayed fruit. 
Similar conditions have since been observed repeatedly where 
oranges were sprayed several times with Bordeaux-oil emulsion dur- 
ing the rainy season or where bluestone was applied to the ground 
around the trees during that season. 
Still another unusual condition developed only on orange trees 
in the form of what is usually called " wither tip." A number of 
twigs died back during the early or middle fall, and moderate but 
general defoliation occurred during early winter for no apparent 
reason. This condition has' also been observed repeatedly on trees 
sprayed with Bordeaux-oil during the summer months, but not on 
unsprayed trees. 
Star melanose (pi. 7, D), described on page 3, occurs on leaves 
and fruit of both the orange and the grapefruit. It, too, is doubtless 
a form of Bordeaux injury, as it has been observed repeatedly on 
trees sprayed excessively with simple Bordeaux mixture as well as 
on those sprayed with Bordeaux-oil emulsion. This blemish has 
never been observed on unsprayed trees. 
There is still another type of spray injury that sometimes develops 
on leaves of orange and grapefruit sprayed with Bordeaux-oil emul- 
sion. This type of spray injury (pi. 7, A, B) is of rather rare 
occurrence and manifests itself as rather large raised areas on either 
surface of the leaf. 
Oil-spray injury. — Young orange and grapefruit trees sprayed 
with oil emulsion in late spring or early summer during the melanose 
spraying season are likely to develop immediately signs of oil injury 
in the form of what appear to be oil-soaked areas commonly called 
" shadows " on the cheeks of the fruit. This is undoubtedly the 
most common form of oil injury, and, except in severe cases, it dis- 
appears before the fruit ripens. By the addition of standard Bor- 
deaux mixture to oil emulsion applied before the onset of the heavy 
rains, melanose can be prevented and oil shadows avoided. 
Another type of oil burn met with in grove spraying is found on 
the lower side of the fruit as solitary depressions of rather regular 
margin where drops of oil spray have collected and dried. This 
injury occurs on both orange and grapefruit, and is usually of minor 
importance except when the oil emulsion breaks. 
The most usual type of Bordeaux-oil spray burn occasionally 
found on the grapefruit and very rarely on the orange is illustrated 
in Plate 6, C. This blemish develops only on the sunny side of a 
