New York Agricultural Experiment Station. 285 



had spread in all directions until eighty-six were infested before 

 the spreading was discovered. 



The treatment and results are shown in Table XIX. Trees 

 fumigated June IG to 24. Average temperature 71°, cloudy. 



Table XIX. — Spbing Fumigation of Plum Trees. 



Dura- 

 Trees. gj^.^,!, tion 



No. Degree of "^ ^'*^* expos- 



treated. Varieties. infestation. uie, Results. Checks. 



Oram. Hours. 



84 Flums: 2 extensive- 0.25 Y2 Scales dead. A large uuniber 



Diamond. ly and re- Trees unin- of Diamond 



mainder jured. Fruit plum trees 



slightly crop equal which bore 



infected. to checks. more than 



average crop 

 of fruit. 



The results shown by Tables XVIII and XIX are strongly in 

 contrast to those of Table XYII where .18 and .25 gram had no 

 appreciable effect upon the scales. In the latter case, however, 

 the trees were fumigated during the winter, while the former 

 were fumigated in June. As the scales were killed by a half 

 hour's treatment in June with the gas at a strength of only .18 

 gram, the indications are that, as might be expected, the scales 

 are more susceptible to the treatment in the spring than during 

 the winter. The weather conditions were such that in each case 

 the trees were damp at the time of treatment. It is to be noted 

 also that although the trees were in foliage when fumigated 

 none were injured and they bore more than an average crop of 

 fruit the following season. 



GENERAL SUMMARY OF FUMIGATION EXPERIMENTS. 



The experiments with buds while not entirely satisfactory 

 owing to the somewhat unfavorable conditions surrounding the 

 treated buds, gave sufficiently uniform results to indicate clearly 

 that the gas was harmless except in the case of the peaches 

 which were evidently injured slightly by the strong gas. Taken 

 as a whole there is but little difference in the percentage of 

 treated buds that set and the checks that were unharmed. In 



