Beans, Fresh Snap 
Losses in snap beans are caused by parasitic fungi, bacteria, 
viruses, root-knot nematodes, and mechanical injury to the seed. 
Root rot and seed decay, caused by fungi, are a major cause of 
loss wherever the crop is grown, particularly in the South. 
Other chief causes of loss are bacterial halo blight, rust, and 
watery soft rot. The common bean mosaic virus and bean yellow 
mosaic virus cause serious losses from stunting of the plants. 
Bald head of seedling beans, caused by injury to the seed in 
threshing, reduces stands in many fields. 
Halo blight is most damaging in humid sections. Rust is most 
common in coastal sections of the South and in southern California, 
Oregon, and Washington; its spread is favored by moist weather and 
coal nights. Watery soft rot causes losses in the Gulf States and 
in western Oregon. The curly top virus causes little loss where 
snap beans are grown for market or canning, but prevents their pro- 
duction in eastern Idaho, Washington, and Oregon. Root-knot nema- 
tode losses are most important in the warmer regions of the United 
States. 
Losses from seed decay and root rots can be reduced by chemical 
seed treatment and rotation, and from bacterial blight by using 
clean seed grown in the semiarid West. Rust can be contrelled by 
sulfur dusts. Crop rotation helps to prevent serious loss from 
watery soft rot. A number of bean varieties are resistant to com- 
mon bean mosaic, but we have none resistant to bean yellow mosaic 
or to curly top. Rotation aids greatly in preventing serious loss 
from root-knot nematodes. 
Beets, Table 
Table beets are not generally injured greatly by disease. Most 
of the loss is caused by seedling diseases, downy mildew, leaf 
spots, root-knot nematodes, and boron deficiency. Black root 
causes damping-off of seedlings; it occurs wherever beets are 
grown. Downy mildew affects all the above-ground parts of the 
plant, particularly the leaves. It is confined almost entirely 
to the Pacific coast. Cercospora leaf spot is common east of the 
Continental Divide, but does not cause severe loss. Root-knot 
nematodes are most damaging to beets in the Westerr States. Boron 
deficiency is probably the most serious disease of beets grown for 
canning in the Northern States; it is characterized by the death 
of young leaves and the presence of blackened tissue in the roots. 
Control measures consist chiefly of chemical seed treatment. to 
reduce loss from black root and application of. boron to the soil. 
Fungicides are not generally used to contre] leaf diseases. 
~ filo 
