338 



FUNGOUS DISEASES OF PLANTS 



XXXVIII. LEAF BLIGHT OF CRANBERRY 



Pestalozzia Guepini Desm. var. Vaccinii Shear 



Shear, C. L. Cranberry Diseases. Bureau Plant Ind. U. S. Dept. Agl. Built. 

 110: 3 8 -39- 1 9°7- 



This fungus is often found upon the cranberry, but it is doubt- 

 less of minor importance as affecting the production of berries. It 

 occurs upon fruit and leaves. The appear- 

 ance of affected berries is not particularly 

 characteristic. The conidia are produced 

 in quantity upon affected leaves placed in a 

 moist chamber. The conidia are usually 

 four-septate with the three central cells 

 dark colored. The hyaline apical cell is 

 furnished with from three to four filiform 



Fig. 161. Pestalozzia Guepini. (After Shear) 

 a, acervulus ; b, conidia ; c and d, germinating conidia 



appendages, and the basal cell has a single shorter appendage. 

 It is interesting to note that in the germination of this fungus 

 one or more germ tubes are developed from the basal hyaline cell. 

 The fungus grows vigorously in artificial culture. The mycelium 

 is hyaline, and it develops a pinkish color when the acervuli are 

 formed. The spores appear in about ten days after sowings are 

 made if conditions are favorable. 



Pestalozzia Hartigii Tub. is a fungus of importance in forest 

 tree nurseries where it attacks the seedlings of young trees of pine 



