200 MANUAL OF FRUIT DISEASES 
Frost-INJuRY 
Caused by the action of low temperatures 
Frost is one of the greatest enemies of the cranberry-grower. 
It is rather erratic in its occurrence, and very difficult for the 
average grower to predict; hence the damage is done before 
any precautions are taken. 
Danger from frost comes throughout the growing-season. 
In June, 1903, the yield in Wisconsin was reduced twenty-five 
per cent, and in early August, sixty per cent. 
It is ordinarily supposed that frost-injury comes about by 
a settling of cold air from the surrounding higher land on the 
bogs. This, however, is regarded as of little importance. 
Frost formation is largely dependent on the temperature of 
the soil, and on heat-radiation from it as influenced by the 
conditions of the atmosphere. The influence of drainage, 
sand, the depth and thickness of the vegetation, especially of 
moss, seem to be controlling factors in the formation of frost, 
and its effect on cranberries. It has been noticed that even 
where the general minimum over a bog was 25° Fahr., if the 
same were well-drained and sanded, it remained unaffected by 
frost; while in adjacent plots which were in a moist condition 
and not sanded, frost destroyed every plant. 
It is advised that plants be sprayed with water every two 
minutes during a frosty night. Or possibly the spraying 
may be done just about sunrise, thus drawing the frost out of 
them gradually before the heat of the sun strikes them. 
REFERENCES 
Whitson, A. R., et al. Preliminary report on cranberry investigations. 
Formation of frost and protection therefrom. Wisconsin Agr. 
Exp. Sta. Rept. 21: 232-233. 1904. 
Franklin, H. J. Report of cranberry substation for 1912. Frost 
LO ae Massachusetts Agr. Exp. Sta. Rept. 25: 210-211. 
1913. 
