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 16 to 24. Average temperature 71°, cloudy. 
TABLE XIX.—SprRING FUMIGATION OF PLUM TREES, 


. Dura- 
rees. re Str’gth ees 
No. Degree of °F £48: expos. 
treated. Varieties. infestation. ure, Resalts. Checks. 
Gram. Hours. 
84 PLUMS: 2 extensive- 0.25 % Seales dead. A large number 
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 XVII 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 EXPHERIMENTS. 
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 
