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cut back for an entire season, as has been demonstrated a number 

 of times with the Canada thistle and other similar weeds. 



One method by which it is thought that the field cress can be 

 exterminated is by persistent spraying, either with an oil spray, 

 a concentrated salt solution or an iron sulphate spray. The 

 spraying should be continued until the plant is completely 

 eradicated. Members of the mustard family are particularly 

 susceptible to the effects of an iron sulphate or a copper sulphate 

 spray. This method is now being used successfully in Maine, 

 New Hampshire and other states for the control of wild mustard 

 or field kale in grain crops. The same method has also been 

 successful in destroying a number of other weeds of the mustard 

 family. Since the Austrian field cress is a member of the mustard 

 family, it is thought that the spraying method offers a reasonable 

 chance for eradication. It is important that the work should 

 be done without loss of time, since the longer the delay, the 

 larger will be the area to be dealt with and the expense will 

 be correspondingly greater. Agricultural authorities of New 

 York, New Jersey and the federal government should be in- 

 terested in this problem. 



Numerous examples can be cited of foreign plants that first 

 occurred in the United States in restricted areas, from which 

 they gradually spread to become noxious weeds causing many 

 thousands of dollars of damage annually. The king-devil, 

 Hieracmm florentinum, was first noted as a weed in a hay field 

 at Cutler, Maine, occurring as a small patch a few feet in di- 

 ameter. No precautions seem to have been taken to prevent 

 its spread until at the present time it is an extremely trouble- 

 some weed from Quebec to New York. Thousands of acres 

 of pasture land have been made unprofitable by this noxious 

 plant. 



Many newly introduced species seem to spread slowly at 

 first. After a period of acclimatization, they seem to suddenly 

 develop aggressive habits and become serious weed problems. 

 A case at point is the wild turnip or rape (a member of the 

 mustard family) which first appeared in the United States 

 about 1863. The species did not prove troublesome until about 

 1887, when it began to spread rapidly. Since then it has become 

 a noxious grain field weed in New York and throughout New 

 England and Quebec. It is entirely possible that the Austrian 

 field cress is now undergoing or has completed a similar period 



