CRANBERRY GROWING 27 



Fertilizers 



No certain ad\-antage is gaine<i b\- fertilizing peat-bottom bogs. Nitrate of 

 soda and acid phosphate often greatly increase the yield on "hard bottom'" 

 areas (sand or clay underneath instead of peat), and 150 pounds of the former 

 and 300 pounds of the latter to an acre is a reasonable application. Potash has 

 little value on any bog. Very late July may be the best time to apply fertilizer. 



Nitrate is likely to promote too much vine growth on peat bottom, especialK 

 if the bog is new. It is generally better to get more vines, where they are desired, 

 by holding the winter flood late than to fertilize for them. Continued use of 

 nitrate impairs the keeping quality of the fruit and encourages weeds. 



Fertilizer helps greatly to repair old bogs out of condition from grub injury. 

 Reground nitrate of soda scattered broadcast early in April, 250 pounds to an 

 acre, reduces haircap moss well and helps the \'ines compete with it. 



Diseases" 



Many fungous diseases attack cranberries. Some seriously affect the vitality 

 of the vines or cause the leaves to drop, and some reduce the crop by blasting 

 the blossoms and young berries or by rotting the berries on the vines and in 

 storage. Late holding of the winter flood (to May 23) tends to curtail such 

 troubles. Bordeaux mixture reduces rot of the berries on the vines and improves 

 their keeping quality; it has been very helpful in some cases, but whether its 

 use generally pays in this State is doubtful. Lead arsenate also has this effect, 

 but its frequent use weakens the vines on sanded areas. Care in handling the 

 fruit in harvesting, separating, sorting, and packing does much to reduce decay 

 in shipment. 



The rot diseases of cranberries caused by different fungi vary greatly in their 

 prevalence in the different cranberry-growing regions of the country. Early 

 rot, which blasts the flowers and young berries and rots the fruit on the vines and 

 in storage, is the most serious of these troubles in New Jersey. As this disease 

 is more completely controlled by spraying with Bordeaux mixture than the others, 

 this treatment is especially valuable in New Jersey. Bitter rot, which rots some 

 berries on the vines and more in storage, and end rot are the leading cranberry 

 rots in Massachusetts. End rot, a late storage rot, is the only serious cranberr\' 

 rot in Wisconsin and on the Pacific Coast. The relative scarcity of the earlier 

 rots accounts largelj' for the success of the Searls variet^'^^ and of water scooping 

 in \^'isconsin and for the greater popularity of the McFarlin variety in the West 

 than in the East. 



New bogs should never be planted with vines having either false blossom or 

 rose bloom. These are the important non-putrefactive cranberry diseases. Both 

 often greatly lower the vitality of the vines and reduce fruit production. Vines 

 affected by false bloossm come to have a witches'-broom development (Fig. 21 

 left), and their flowers open facing upward (Fig. 21 right) instead of turning 

 down as healthy cranberry blossoms do. It is a virus disease, spread by a leaf- 

 hopper (Fig. 22), and can be controlled by checking the leaf hopper with 5 percent 

 DDT dust, clear high-grade pyrethrum dust, or dusts containing rotenone, 50 

 pounds to an acre (Fig. 23). Rose bloom is a fungous disease which causes new 

 shoots to be greatly enlarged and rose-colored, the vines sometimes appearing 

 as though they were in full bloom. It affects late varieties most, especialK- 



" Technical Bulletin 258 of the United States Department of Agriculture is the best genera', 

 account of cranberry fungous diseases. 



'- This variety has not succeeded in the East because of the rotting of it« fruit here. 



