7() 
COT.OR ADO E X PERI AI E N T S^I’ATION 
RASPBERRY 
Anthracnose (Plectodiscella veneta) (79) — This disease occurs 
also on the blackberry but is more destructive on the raspberry. It is 
not of great importance in Colorado. Both leaves and the canes are 
affected, although the gi-eatest injury is to the canes. At first small 
purplish spots are produced which later increase in size and become 
grayish white in the center. The margins of the spots may run to- 
gether and girdle the cane. Affected canes often crack badly. The 
spots formed on the leaves are similar to those on the canes except 
that they are smaller. The dead tissue often drops out, giving the 
leaves a shot-hole effect. Fruit and pedicels may also be attacked. 
Diseased canes should be eradicated before the spring season. 
Clean, healthy plants should be set. Shoit rotations should be prac- 
ticed. Spray with Bordeaux mixture (4-4-50) as follows: (1) before 
the leaves appear, (2) after the leaves are well formed and when 
the shoots are about six inches high, (3) just before the blossoms 
appear. If necessary later sprays may be applied at ten day in- 
tervals. 
Spur- Blight (Mycosphaerella rubina) (69) — In some years this is 
a serious disease of the raspberry in Colorado. It reduces the crop by 
reducing the number of fruit spurs and killing the buds. Diseased 
canes are extremely brittle and break easily when being put down 
in the fall or taken up in the spring. 
The first symptoms are seen about the first of July. Chocolate 
brown spots are formed over the lower nodes of the canes and often 
also along the internodes and on the leaf petioles. The buds from 
the lower nodes are either killed outright or are so weakened that 
only poor shoots are produced. No fr'uit is developed on the lower 
half of the canes. 
Spur-blight may be conti'olled by spi'aying with Bordeaux mix- 
ture (3-3-50) with two pounds of resin-fish-oil soap added as a | 
sticker. The spray should be applied to the young canes and not j 
to the fruiting canes. Spray (1) about the first of fJune when the I 
canes are 8-12 inches high, (2) two weeks later, (3) two weeks after ! 
the second spray. Remove and burn all old fruiting canes as soon 
as the berries have been gathered. 
Leaf-Spot (Septoria rubi) — I^eaf-Spot occui’s on rasi)beri*ics, 
''I'he Colored l^late on the opposite i)a,i4'e illiislrale.s llte spur-hlif;hl. ( )rif;innlly n.sed , 
in Bnlletin 206 , by Saekett. ! 
