16 BULLETIN 1434, U. S. DEPARTMENT OF AGRICULTURE 
low, wet ground on either side of a cross ditch, and the berries from 
these two plots developed considerably more rot than the unsprayed 
check a short distance away on higher and drier ground. Since the 
relative proportion of infection is likely to vary to some extent, it is 
not surprising to find that contradictory results were sometimes ob- 
tained even on the small, comparatively uniform areas used for the 
experimental plots. 
In the second place, it is impossible to establish and maintain 
complete coverage of all the fruits in a sprayed area. The quantity of 
spray applied per acre, the care with which the spray is applied, and 
the depth of vines through which the spray must penetrate in order 
to reach the berries are three very important factors in determining 
the proportionate number of berries which receive the protective 
covering of spray. It is evident that thoroughness of application is 
of great importance in obtaining successful results from spraying. 
It should also be emphasized that berries in the late-storage tests 
were screened early in the season and were then kept boxed until 
sampled. The proportion of rot present in such a case is not an 
index of the percentage which would be found in commercial berries 
in the market at the same time of year, because the latter would 
have been screened much later and all early-developed rot removed. 
CONCLUSIONS FROM SPRAYING AND STORAGE TESTS 
Storage tests conducted over a period of four years lead to the 
following conclusions: 
Some years an excessive percentage of storage rot develops in most of the 
unsprayed cranberries produced in the Pacific coast region. 
Each year an excessive percentage of rot develops in certain bogs and 
apparently in particular varieties, if uncontrolled. 
Two applications of Bordeaux mixture — the first made in the hook stage or 
just as the bog begins to bloom, the second in the after-blossom stage, as the 
vines go out of bloom — control the development of storage rots satisfactorily, pro- 
vided the berries are harvested and handled with sufficient care. 
Of the two applications, that at the hook stage is the more essential. 
DUSTING EXPERIMENTS 
In the 1925 spraying tests a parallel series of plots was treated 
with a commercial preparation of lime-copper dust for the purpose of 
getting comparative data on spraying and dusting as control methods 
for cranberry rots. The dust used in the test contained 25 per cent 
by weight of monohydrated copper sulphate and 75 per cent of hydrated 
lime. It was applied by means of a hand-blower dust gun fitted with 
two nozzles, a method which is not very satisfactory on cranberry 
vines, because of the habit of vine growth. At first it was attempted 
to apply the dust at a definite rate per acre, but this was abandoned 
after a few trials, and thereafter an excessive quantity was used to 
insure some dust reaching all the vines. Winds, which blow almost 
constantly over the bogs in this region, often carried away most of 
the dust before it could settle into the vines. 
The results of the dusting tests are given in Table 9. It is seen 
that the dust failed to give as consistently good control as did the 
spray, although in a few instances it proved equal to the Bordeaux 
mixture. This inconsistency of results was expected, when so much 
difficulty was encountered in the attempt to spread the dust uniformly 
