190 CLOVERS 



greatly interfere with the harvesting of the crops. 

 They are destroyed by giving them poisoned food, 

 trapping, shooting, and suffocating through the use 

 of bisulphide of carbon. Poison is frequently ad- 

 ministered by soaking grain in strychnine or drop- 

 ping it on pieces of potato and putting the same in 

 or near the burrows. Bisulphide of carbon is put 

 upon a rag or other substance, which is put into the 

 burrow and the opening closed. 



Dodder is a parasitical plant introduced, prob- 

 ably, in seed from Europe, which feeds upon alfalfa 

 plants, to their destruction. The seeds of alfalfa 

 sometimes become so impregnated with the seeds of 

 dodder that the latter will grow where the seed is 

 sown, thus introducing it to new centers. The 

 dodder starts in the soil and soon throws up its 

 golden-colored thread-like stems, which reach out 

 and fasten on the alfalfa plants that grow sufficiently 

 near. The dodder then loses its hold upon the soil 

 and gets its food entirely from the alfalfa plants, 

 which it ultimately destroys. But since the seeds of 

 the dodder remain at least for a time in the soil, and 

 the adjacent soil becomes infected with them, the 

 circles in which the dodder feeds continually widen. 

 In certain parts of New York State some fields have 

 become so seriously affected as to lead to investiga- 

 tions conducted through officials from the State ex- 

 periment station. Pending these investigations, the 

 exercise of great care in the purchase of seed and the 

 immediate plowing of the infested areas are recom- 

 mended. 



Some reference has already been made to injuri- 



