214 FUMIGATION METHODS 



' ' From this summary it will be noticed that the gas 

 at o.i 8 and 0.25 gramme had little or no effect upon 

 the scale when the fumigating was done in the 

 winter; but that 0.30 gramme was strong enough to 

 kill the scales. Also that the spring treatment resulted 

 in killing the scales with the gas at o. 18 gramme and 

 only one-half hour exposure. All of the plum trees 

 treated were European varieties, and both plums and 

 peaches were healthy, vigorous trees. We used the 

 box fumigator shown at Figs. 43 and 81 in all cases. 

 Fig. 8 1 shows our improved method of fastening the 

 door on our fumigator. 



' ' All of the trees were badly infested with the 

 scale. Where the term ' scales dead ' is used it 

 means that after very careful search at various times 

 during the summer following the experiment no live 

 scales could be found. The statement that the trees 

 were uninjured means that there was no effect on the 

 foliage and fruit buds. 



" The buds included in the fumigation experiment 

 were of the following varieties : Apples Jonathan, 

 Fall Pippin, Oldenburg, Ben Davis, Fameuse, and 

 Transcendant. Cherries May Duke, Windsor, and 

 Early Richmond. Pears Anjou, Bartlett, Seckel, and 

 Kieffer. Peaches Elberta, Early Crawford, Blenheim, 

 Early Rivers, Beersmock, and Alexander. Plums 

 Italian Prune, Reine Claude, Bradshaw, Shropshire 

 Damson, Burbank, Yellow Spanish, Yellow Egg, Lom- 

 bard, and De Soto. 



' ' The buds were fumigated in a small box made 

 especially for the purpose. The gas was used at the 

 following strengths: o. 18, 0.22, and 0.30 gramme. 



