DISEASES OF CROPS 951 



STRAWBERRY 



Leaf Spot (SphcereUa fragarice [Tul.], Sacc). — This is the most promi- 

 nent of the diseases of the strawberry. It causes small leaf spots with 

 white or ashy centers and purple or red borders. These spots frequently 

 unite, forming irregular blotches. It reduces the vigor of the plant and, 

 therefore, the quality and quantity of the fruit. 



Treatment. — The soil should be well drained and rotation of crops 

 practiced. Cutting over the beds and burning of the tops is advantageous. 

 Spraying with Bordeaux mixture will reduce the disease to the minimum, 

 but there is doubt as to whether this treatment will prove profitable. 



CRANBERRY 



Scald or Blast (Guignardia vaccinii, Shear) — This fungus attacks the 

 blossoms or the fruit soon after the falling of the blossoms, causing the berry 

 to shrivel and turn black. This form of the disease is known as the " blast." 

 The form known as "scald" causes small, soft, light-colored, watery spots 

 which spread over the entire fruit, sometimes causing a zone effect. The 

 disease also attacks the leaves, causing irregular, reddish-brown spots. 

 The disease is likely to become worse from year to year and to prove very 

 destructive. 



Treatment. — Careful irrigation, raking and burning of the dead 

 material and sanding the bogs are advantageous. Selection of resistant 

 strains for planting, and spraying with Bordeaux mixture about five times 

 during the season w T ill control the disease. 



Rot (Acanthoshynchus vaccinii, Shear). — This fungus causes a 

 rot very similar to the scald and can be controlled by the same treat- 

 ment. 



Anthracnose (Glomerella rufomaculans [Berk.] Spaul. and von 

 Schrenk; vacinii, Shear). — This fungus is the same as the one causing the 

 bitter rot of the apple. It causes a rot veiy similar to and almost indis- 

 tinguishable from the scald and can be controlled by the same treatment. 



GOOSEBERRY 

 Powdery Mildew (Sphatrotheca mors-uvce [Schw.] Berk, and Curt.) — ■ 

 Very similar to the mildew on the apple and other fruits and should receive 

 the same treatment. 



CURRANT 



Anthracnose (Pseudopeziza ribes, Kleb.). — This very common disease 

 of the currant attacks the leaves, causing many small brown or black spots, 

 followed by a yellowing of the entire leaf which falls prematurely. The 

 disease also attacks the canes and the fruit, causing small black, sunken 

 areas. It is carried from year to year on the canes. 



Treatment. — Remove the old canes and spray with Bordeaux mix- 

 ture in the spring just before the buds open, again after the leaf 



