1908.] Gooseberry Black-Knot. 681 



The fungus does not show itself externally until the branch 

 is dead, or nearly so, when its fruiting bodies burst through the 

 bark under the form of large elongated and transversely 

 grouped black warts. These warts are often quite numerous 

 and give a blackened appearance to the branch. 



FIG. I.— Black-knot on gooseberry stem (nat. size). 

 fig. 2.— Black-knot on red currant stem (nat. size). 

 fig. 3. — Spores of the fungus (highly mag.). 



fig. 4. — Section through a black fruiting pustule of the fungus (slightly mag.). 



Treatment. — Spraying is of no avail in the case of this fungus. 

 On the first appearance of disease, indicated by wilting of the 

 foliage, infected branches should be removed and burned. 

 Bushes should be kept clear of aphides and currant scale. 



