SUMMARY. 53 



the sprayod fruit diseased, wiiile a«.J per cent of the unsprayed fruit 

 was diseased. In other words, four times as much of the unsprayed 

 fruit as of the sprayed fruit decayed between the time of pickinji" and 

 marketing. The decay which developed was apparently caused by 

 the dormant infection. 



CoHt of Hpnn/'uif/. — The cost of spraying- as it was done in these 

 experiments averaged from $15 to $20 per acre, the Bordeaux mixture 

 being applied at the rate of 4 barrels, or 200 gallons, per acre at each 

 application, making for five applications a total of 1,000 gallons per 

 acre. The cost would ])r()l)al)ly vary somewhat under different condi- 

 tions and different methods, but in no instance should it exceed $20 

 per acre. 



SUMMARY. 



There are four serious fungous diseases of the cranberry — scald, 

 caused by GiiUjnardia rarchiu; rot, caused by Acanthovhuhchus^ rac- 

 cinii; anthracnose, caused by Glomerella riifouKiculditH racrinil, and 

 hypertrophv, due to E.i-oIxd^'xI'iiivi o.vycoeci. The first three diseases 

 mentioned have heretofore been confused and considered as one. 



Life histcM-y studies have shown that Giiignardia mrcinii produces 

 two forms of fructification — pycnidial and ascogenous — and is 

 closely related to Guignardia hidweUii, which causes the black-rot of 

 the grape. 



Similar studies of Acaittltorhynchns raccimi reveal only ascogenous 

 fructifications, but very striking and characteristic appressoria, which 

 perhaps fill in part the place of a pycnidial form, are j^roduced. 



Glomerella nifomacidans raccinii is also found to produce both 

 conidial and ascogenous forms. 



The production of ascogenous fructifications appears to depend in 

 both Guignardia raccimi and Glomerella rufomacrdans raccinii 

 chiefly upon some inherent potentiality of the race, strain, or genera- 

 tion from which the hypha? or spore used in the culture are derived. 

 The composition of the culture medium and the conditions of temper- 

 ature, moisture, and light are relatively unimportant factors. 



The fungi producing scald, rot, and anthracnose, as well as Pesta- 

 lozzia gnep'nii imccinii, are able to live in the tissues of cranberry 

 leaves and fruit in a more or less dormant or noninjurious condition 

 for a considerable i^eriod and may apparently at any time develop 

 rapidly and destroy the tissues when conditions are favorable. 



Thirteen other fungi have been found affecting cranberry fruit, 

 most of which have, however, not shown indication of particular 

 pathological importance. Sixteen different species have been found 

 on either stems or leaves. Most of these do not seem to cause serious 

 injury to the plant. 



110 



