646 IOWA DEPARTMENT OF A&RICULTURE. 



The work was done at the Trigg orchard, located at Rockford, Floyd 

 county. There are 2,900 trees in this orchard. They were planted in 

 1895 and 1896, which makes them now ten and eleven years old. They 

 are mostly of the Wealthy and Patten Greening varieties. In 1905 the 

 Patten Greening bore a good crop and perhaps for this reason they did not 

 set very much fruit last season. So far as can be determined the crop of 

 Wealthy in 1905 was largely destroyed by the scab fungus. In 1905 the 

 Wealthy set considerably more fruit than the Patten Greening, but not a 

 good crop. The average yield for the orchard was less than one-fifth 

 bushel per tree, while in one of the plots under experiment the yield 

 averaged two bushels per tree. Had the entire orchard yielded propor- 

 tionately as much as this experiment plot it would have produced over 

 5,000 bushels instead of less than 500. This would have made the spray- 

 ing much more profitable, for the cost of spraying the whole crop would 

 have been but little greater than the cost of spraying the small crop which 

 the orchard produced. 



The entire orchard was sprayed with the exception of the plots of 

 trees called I and IV, which were located in a portion of the orchard 

 where there appeared to be the best prospect for a good crop of fruit. 

 Each of these plots contained fifteen trees. Plot I contained six Patten 

 Greening and nine Wealthy trees. Plot IV contained three Patten Green- 

 ing and twelve Wealthy trees. The corresponding sprayed plots were num- 

 bered II, III and V. Plot II lay immediately south of plot I and con- 

 tained likewise six Patten Greening and nine Wealthy trees. Plot III 

 lay immediately north and plot V immediately south of plot IV. Like 

 plot IV, they each contained three Patten Greening and twelve Wealthy 

 trees. 



The first spraying was given just before the blossoms opened, the second 

 just after the blossoms fell, and the third from June 21st to June 25th. 

 About the first of August the fourth spraying was made to combat the 

 second brood of the codlin moth. The materials used were Bordeaux 

 mixture, paris green and arsenate of lead. All of the trees except the 

 checks were sprayed each time except at the last treatment, when only 

 those havipg more than a hatful of apples were sprayed. 



TOTAL YIELDS COMPARED. 



Taking into account all grades of fruit, a comparison of the sprayed 

 plats with unsprayed plats shows in every case a decided increase in the 

 total yield of the sprayed trees. A comparison of plot I and plot II shows 

 that the yield of the sprayed Patten Greening was 164 per cent tha 

 the unsprayed, and the yield of the sprayed Wealthy was 123 per cent 

 that of the corresponding unsprayed Wealthy. When the unsprayed plf^t 

 IV is likewise compared with the corresponding sprayed plats III and V 

 it is seen that the yield of the sprayed Patten Greening is respectively 422 

 per cent and 255 per cent that of the unsprayed, while the yield of the 

 sprayed Wealthy is respectively 546 per cent and 653 per cent of that of 

 the unsprayed Wealthy. In other words, sprayed Wealthy yielded in one 

 case five and one-half times as much, in another case six and one-half 

 times as much, and in the third case twelve and one-half times as much 

 as the corresponding unsprayed Wealthy, while sprayed Patten Greening 



