DODDER: IN“ALPALFATSERD? 
F. C. STEWART anp G. T. FRENCH. 
Dodder is a yellow, thread-like twining weed which is exceed- 
ingly troublesome in alfalfa fields. It appears in circular spots 
three to thirty feet or more in diameter. At the center of the 
spot the alfalfa is killed out while around the margin the ground 
is covered with a mat of yellow threads which twine closely 
about the stems of the alfalfa plants and slowly strangle them. 
The spots increase in size from year to year. Many fields have 
been completely ruined by dodder. It is not often injurious to 
other crops (except red clover), but once established in an alfalfa 
field it is very difficult to eradicate without killing the alfalfa. 
In most cases dodder gets into the field through the use of 
impure alfalfa or clover seed. Hence, it is of the utmost impor- 
tance that no dodder-infested seed be sown. ‘Since much of the 
alfalfa seed on the market in New York State is more or less 
infested with dodder it is often difficult to obtain dodder-free 
seed. The statements of seed dealers should not be relied upon. 
Most of the alfalfa seed in this State is handled by hardware 
merchants who, themselves, do not know dodder seed. As these 
seeds are much smaller than those of alfalfa they may be easily 
overlooked. Good-looking seed, otherwise clean, may be badly 
infested with dodder. Even so small an amount as one dodder 
seed per pound makes alfalfa seed dangerous to sow ae prop- 
erly cleaned. 
Farmers are advised to protect themselves against this weed; 
by sowing no alfalfa seed until it has been pronounced dodder- 
free by a seed expert or has been thoroughly sifted as directed 
below. ‘The safest method is to have the seed both analyzed 
and sifted. This Station will make analyses of alfalfa seed free 
of charge. Samples should contain at least one ounce of seed, 
taken from the bottom of the bag. The packages should be ad- 
dressed: Experiment Station, Geneva, N. Y.; and should be 
plainly marked with the name and address of the sender. 


* A reprint of Circular No. 8, new series. 
