EXPERIMENT STATION WORK, LI. 17 



crops, among them, according to the reports from the North Dakota 

 Station, being the very troublesome Canada thistle. 



The explanation of the action of the chemicals seems to be about 

 as follows: The chemical, which is corrosive, attacks the young and 

 tender tissues of the rapidly growing weeds, causing their destruc- 

 tion, while there is little if any injury to the grain crop, particularly 

 if it is a winter grain or one that was sown early in the spring, so 

 that the crop has gained considerable growth before the spraying. 



Investigations at the North Dakota Station with chemical means 

 for the control of weed pests have shown that in addition to weeds 

 in fields, such persistent weeds as dandelions may be eradicated in 

 lawns, parks, and meadows by thorough spraying with the iron sul- 

 phate solution without any injury to the lawn or pasture grass. In 

 the region about Fargo, where the experiments were conducted, spray- 

 ing once a month or every six weeks throughout the year was found 

 to keep the dandelion in check. For spraying lawns the applica- 

 tion should be made a few days after the grass has been cut, with a 

 solution of about 2 pounds of iron sulphate to a gallon of water. 

 The spray should be forcibly applied, not merely sprinkled over the 

 weeds, on a bright sunshiny day, and the lawn should not be mown 

 for two or three days after the spraying. Heavy rains soon after 

 the spraying will destroy the weed-killing power of the solution. 

 Wherever chemicals are used for weed eradication on lawns it will 

 be found advisable to scatter grass seed over the lawn each spring 

 and fall. 



In many regions alfalfa and clover fields are infested with dodder, 

 a parasitic plant that may be recognized by its yellow, thread-like 

 stems which entwine the plants. Hiltner says that dodder may 

 be destroyed by spraying infested areas with an 18 to 20 per cent 

 solution of iron sulphate. The immediate effect of the chemical is to 

 blacken the clover or alfalfa, but after a short time the crop recovers 

 and is as vigorous as ever, while the dodder has been completely 

 destroyed. In South Africa, 6 spraying alfalfa with sodium arsenite 

 at the rate of one-half pound to 5 gallons of water when well applied 

 was found to destroy dodder with little injury to the alfalfa. 



MAKKET CLASSES AND GEADES OF SHEEP/ 



A recent bulletin of the Illinois Station, by W. C. Coffey, defines 

 and illustrates the various classes and grades of sheep recognized on 

 the Chicago and other large markets. The information is intended 



a Prakt Bl. Pflanzenbau u. Schutz, n. ser., 6 (1908), No. 4, p. 40. 

 6 Agr. Jour. Cape Good Hope, 32 (1908), No. 2, p. 152. 



c Compiled from Illinois Sta. Bui. 129. For classification of other farm ani- 

 mals see U. S. Dept. Agr., Farmers' Buls. 222, p. 24 ; 334, p. 22. 

 360 



