28 STATE HORTICULTURAL SOCIETY. 



Through the kindness of Judge W. R. Wilkinson, of Altenburg, 

 Mo., the Station was not only enabled to make experiments with car- 

 bon bisulphide and tobacco dust in his apple orchard consisting of ten- 

 year-old bearing trees, but we received valuable assistance in the ex- 

 periments from his personal attention, and from the help he placed at 

 our disposal. 



On the 29th of June, 35 trees in his orchard that were suffering 

 the most from the wooly-aphis, and some of which no doubt would 

 have died soon, were selected for the following experiments: Twenty 

 of these trees were treated with carbon bisulphide. This was injected 

 into the ground close to the trunk of the tree by means of the injector 

 to be described later. The quantity injected varied from one to three 

 fluid ounces per tree, and was injected in one place on some, and in 

 two and in three places on others. The result was that within a month 

 every tree was either wholly or partially dead. Wherever the liquid 

 carbon bisulphide came in contact with the tree, it killed that portion 

 of it. Hence extreme caution should be exercised in using this sub- 

 stance. Profiting by this experience, other and more extended experi- 

 ments were immediately undertaken at the Olden Fruit Farm, with 

 the same substance, but this time with success. These experiments 

 are described later. 



The remaining 15 trees in Judge Wilkinson's orchard were treated 

 with tobacco dust in the following way: The earth was removed with 

 a hoe from around the trunk of a tree for a distance of two feet and 

 to a depth of four to six inches. In this excavation was evenly dis- 

 tributed from two and one-half to five pounds of tobacco dust, care 

 being taken to place it close to the trunk also. The tobacco was then 

 covered over with the earth to prevent the wind and rain from displac- 

 ing it. In removing the earth from around these trees it was plainly 

 seen that they were very baaly infested with the wooly-apbis. On the 

 ]5th of August these same trees received another equal supply of to- 

 bacco dust. On the 30th of October I visited the trees in company 

 with Judge Wilkinson and most carefully inspected them. Out of the 

 15 trees thus treated only two were found that bad any signs of living 

 wooly-aphis on the roots, and these two trees had but one small colony 

 each at the surface of the ground on some small roots where the to- 

 bacco had evidently not been applied close to the trunk. These two 

 trees had been treated with two and one-half and three pounds of to- 

 bacco dust respectively. As far down as we could well dig, the aphis 

 had all been killed. None of the trees treated with the tobacco dust 

 died or were injured. This orchard is on the side of a steep hill. Thus 

 it will be seen that in this case very badly infested 10-year-old apple 



