208 ILLINOIS STATE ACADEMY OF SCIENCE 



were exposed at the same time by attaching two slides to 

 each paddle. 



Observations made on this date show that approxi- 

 mately the same numbers of spores were present at ele- 

 vations of 100 to 2,000 feet. At 6,000 feet there were 

 about six-tenths as many spores as at 2,000 feet. At each 

 elevation there were twice as many aeciospores as ure- 

 diniospores and few teliospores were found from 100 to 

 2,000 feet. 



RESULTS FROM SERIES 4 



These slides were exposed on September 18, 1922, and 

 the results are given to show the presence of the different 

 spore forms late in the season. The exposure period was 

 three minutes over an area free from any escaped bar- 

 berries, and probably harboring few cultivated bushes. 

 No aeciospores whatever were found on microscopic ex- 

 amination. A very large number of uredinio spores were 

 found and a decidedly increased number of teliospores, 

 all of which is in direct keeping with the advanced season 

 and the other conditions under which the exposures were 

 made. 



SUMMARY 



The campaign for the eradication of the common bar- 

 berry began in Illinois in the spring of 1918. Practically 

 all of the cities and towns were surveyed during the first 

 two years. The activities of the past three years have 

 been devoted to the farm-to-farm survey of 15 counties 

 in the northern part of the State and a resurvey of the 

 city properties in these counties. 



Illinois has an unusually large number of escaped bar- 

 berries. In most cases, these escaped bushes are growing 

 in timber land, brushy pastures, or on rocky hillsides 

 which are of rough topography and present serious prob- 

 lems of successful eradication. The spread of escaped 

 barberries is correlated with the type of soil and topogra- 

 phy of the land over which they scatter. Results of ex- 

 periments show that the most feasible method of killing 

 barberry bushes in rocky situations is by the application 

 of salt. An average-sized bush can be killed with 10 

 pounds of common crushed rock salt piled over the crown. 



