24 
COI.OKADO ExPEIJIISIEM’ StATION 
Dodder (Cuscuta spp.) (3)— Dodder is a common alfalfa parasite. 
It is widely distributed over the state although it is most prevalent 
in southern Colorado. Its injury is usually confined to relatively 
small tracts of alfalfa. These affected spots are covered with a 
tangled mat of yellow threads that twine closely around the plant. 
Affected plants are greatly stunted and are often killed. 
The dodder plant is a true seed plant and has small white 
flowers. The dodder seed germinates in the soil and begins its 
growth just as any other plant but when it comes into contact with 
Dodder on alfalfa; an en- 
larged drawing to show meth- 
od of attachment (after 
Longyear). 
the alfalfa plant it twines itself about the stem, sends little root- 
like structures (haustoria) into the alfalfa stems and robs the plant 
of its food. As soon as it has established itself on the alfalfa plant 
it loses its connection with the soil and lives entirely upon the 
alfalfa. 
When affected areas are small, infected plants should be cut close 
to the ground beginning at the outside of the area and working in- 
ward; then burn the plants when dry and watch for any renewed 
growth. 
If affected areas are extensive mow the entire crop closely, 
allow the hay to dry and then burn it. Plow the field and keep in 
cultivated crops for several years. 
Dodder seed resemble alfalfa seed and are often found mixed 
with them. It is often spread and introduced into new areas in this 
way. Samples of all alfalfa seed should be sent to the Colorado seed 
laboratory for examination before planting. 
APPLE 
Fire Blight (Bacillus amylovorus) (4), (5), (b) — This is the same 
disease that affects pears. It does nearly as much datiiage on the 
