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JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 12 



small plot being used, were dug up and examined. A total of 71 yards 

 or 1983 plants (average of 9.3+ plants to the foot or 694,468 to the 

 acre, if rows are 7 inches apart) were actually dug up and examined. 

 The accumulative percentages every five yards were as follows: 31 + , 

 27 + , 33-, 33 + , 35 + , 34 + , 33-, 32 + , 32-, 31 + , 30 + , 29 + , 

 29 + , 29-, 29-, the average for the total 1983 plants being 29- 

 per cent, which we can consider as the average percentage of infesta- 

 tion of the plot. 



The various methods were tried to determine the most satisfactory 

 means of making counts and these included the picking method, one- 

 third square yards, linear yards, and linear feet. The results are 

 tabulated in Table II. 



Table II— Results of Counts by Different Methods, 1918 



Although none of the methods used were far from correct, the linear 

 foot and picking methods were most nearly accurate and from other 

 tests, repeated at a number of our other sowing plots, they are more 

 to be depended upon. This is as might be expected, since a larger 

 number of small areas scattered over the field should give more nearly 

 accurate results from the entire field than the same total area taken at 

 fewer places in the field. Of the two most accurate methods just 

 mentioned the picking method has been dismissed as the least satis- 

 factory for experiment plots, first, because it requires some practice, 

 second, because itas practically useless in the spring or even in the fall, 

 if the wheat plants have tillered abundantly, and third, because it is 

 desirable to use the same method in fall and spring. Since the linear 

 foot method lacks the disadvantages just named, and is simple, requir- 

 ing no previous practice, and is practically as accurate as any other 

 means, we have concluded that it is the most correct and satisfactory. 



On the other hand, the picking method is very useful for hastily 

 determining fall infestations when making surveys over large areas and 

 for this purpose can frequently be used to advantage. 



In many cases it is possible to obtain relatively accurate data by ex- 

 amining plants from above and without digging them up to determine 



