GUIGNARDIA 169 



Bordeaux mixture, 5-5-50, when the third or fourth leaf is 

 showing ; again with the same mixture just when the blossoms 

 are swelling; thirdly, with the same mixture soon after the 

 leaves have fallen. Remaining applications depend on the 

 weather. Use Bordeaux mixture until middle of July, after- 

 wards use ammoniacal copper-carbonate, 5-3-50, which will 

 not discolour the grapes, is nearly as efficient as Bordeaux 

 mixture, and is perfectly harmless to the berries. 



Prillieux, Malad. des Plantes Agric, 2, p. 157 (1897). 

 Reddick and Wilson, Cornell Univ. Agric. Expt. Sta., 

 Bull. 253 (1908). 



Viala, Les Malad. de la Vigne, ed. 3, p. 190. 



Cranberry blast and scald. These diseases are caused by 

 Guignardia vaccinii (Shear). The term blast is applied when 

 the flower or very young fruit is attacked, the latter becoming 

 covered with the conidial form of the fungus, which causes it 

 to shrivel at an early age. Scald is applied when the full- 

 grown fruit is attacked. The first indication is the appearance 

 of a minute, light-coloured, watery spot upon its surface. 

 This spreads, usually in a concentric manner, until finally the 

 whole berry becomes soft. Frequently the diseased area is 

 marked by dark-coloured concentric rings. The disease 

 also attacks the leaves sometimes, causing a reddish-brown 

 spot, which eventually bears the conidial or ascigerous form 

 of fruit. The most destructive cranberry disease known in 

 the United States. 



Perithecia globose, black, with a slightly prominent mouth. 

 Asci 8-spored, sessile ; spores hyaline then yellowish-brown, 

 shortly elliptical or subrhomboid, 13-16x6-7 \i. Perithecia 

 of conidia like those of the ascigerous condition ; conidia 

 hyaline, obovoid, 10-5 X 135 X 5-6 fx, with a hyaline appendage 

 at the apex. 



Five applications of Bordeaux mixture, mixed with resin and 

 fish-oil soap, checked the disease. 



Shear, C. L., U.S. Dept. Agric, Bureau of Plant Industry, 

 Bull. No. 1 10 (1907). 



Guignardia theae (Bernard) causes spots on living leaves of 

 Thea assamica, somewhat resembling those due to Pestalozzia 

 guepini. 



