24 



BULLETIN 289 > IT. S. DEPARTMENT OF AGRICULTURE. 



Table VII. — Average seed yield of clover heads which vjere struck horizontally with different 

 types of brushes and either protected or unprotected from insects at La Fayette, Ind. , in 

 1913. 



Brush used. 



Strokes 



per 

 treat- 

 ment. 



Heads left uncov- 

 ered. 



Heads covered with 

 tarlatan. 



Heads 

 worked. 



Seeds per 

 head. 



Heads 

 worked. 



Seeds per 

 head. 



A 



1 



1 

 1 



1 

 1 



1 



3 

 5 

 5 

 3 



5 

 5 



37.4 

 38.8 

 50.1 

 60.8 

 57.5 

 CO. 1 



1 

 1 

 2 

 1 

 1 

 2 







B 







E 













Do 







Do 











Table VII shows that in each case of the heads left uncovered the 

 check produced the most seed. As in Table VI, the brushes appar- 

 ently reduced the seed production. It will be noted also that both 

 the brush-treated and untreated heads produced no seed when 

 protected from insect visitation. 



Experiments to test the relative efficiency of horizontal strokes 

 with the different brushes were also conducted at Ames, in the sum- 

 mer of 1911. Ten plats 4 feet square were used. These plats were 

 marked off by placing stakes at the corners and connecting these 

 stakes with heavy cord. Plats 1 to 8 were each given one treatment 

 on each of three consecutive days, with brushes B, A, E, C, F, D, G, 

 and H, respectively, and plats 9 and 10 were left as checks. Dupli- 

 cate tests, using the same brushes, respectively, on plats 37 to 44 

 were also made. The results are shown in Table VIII. 



Table VIII. — Average seed yield per head obtained when clover heads were struck horizon- 

 tally with different types of brushes at Ames, Iowa, in 1911. 





Strokes 

 per treat- 

 ment. 



Treat- 

 ments. 



Original tests. 



Duplicate tests. 



Brush used. 



Plat 



No. 



Heads 

 worked. 



Seeds 

 per head. 



Plat 



No. 



Heads 

 worked. 



Si eds 

 per head. 



B 



1 

 1 

 1 

 1 

 1 

 1 

 1 

 1 



3 

 3 

 3 

 3 

 3 

 3 

 3 

 3 



1 

 2 



3 



4 

 5 

 6 

 7 

 8 

 9 

 10 



464 



476 

 457 

 322 

 440 

 435 

 320 

 430 

 532 

 470 



44. S 

 41. 1 

 42.6 

 46. 2 

 43. 9 

 36. 2 



45. 1 

 41.0 

 55. 4 

 50.9 



37 

 3S 

 39 

 40 

 41 

 42 

 43 

 41 

 9 

 10 



438 

 515 

 490 

 185 

 470 

 1 15 

 460 

 132 

 532 

 470 



44.9 



A 



43.2 



E 



c 



30.1 

 42.5 



F 



D 



47.5 

 33.0 



G . . . 



39.9 



H 



42.9 



Check 



55.4 



Do 







50.9 











Table VIII shows that in every case where brushes were used the 

 seed production fell below the yield of the check plats. 



From the results obtained in Tables VI, VII, and VIII it is con- 

 cluded that at least horizontal strokes with the brushes in question 

 reduced the seed product ion on account of the flowers being muti- 

 lated by the. brushes, 



