EFFECT OF PUM IGA DION <»N TREES. , r ).S 
tree as a whole. This tree was observed in Full bloom od April 1, and 
ten months after the treatment appeared as vigorous as any tree in 
the grove and bore more than the average crop of fruit. In the 
experiments with the bell tent of 6$-ounce drill, shedding of conse- 
quence occurred only in the case of experiment X.2. This tree was 
fumigated on January 29, beginning at 4.41 and ending at 7.50 p. m. 
It was estimated that the shedding amounted to about 30 per cent 
in tins case. 
In experiment 45.36 the exposure began at 3.07 p. m. in bright sun- 
Light with the temperature at 7.")° F. The tent had been in position 
for thirty minutes preceding the introduction of the chemicals, and 
the inside temperature was 4£° higher at the beginning than the out- 
side temperature mentioned above. The tent was in direct sunlight 
during the entire forty-five minutes of exposure, and doubtless the 
inside temperature rose to S2 J or 83°. As shown in Table IV, the 
amount of potassium cyanid used was 4\ ounces less than the 
amount recommended in the table given in the appendix. The 
leaves were curled as a result of drought at the time of the fumiga- 
tion and no shedding of leaves or injury of any kind to the tree could 
be detected by subsequent examinations. 
An overdose is indicated by the scorching of the foliage on entire 
twigs. This is more likely to occur near the tops of the trees. In 
such cases several twigs, each 6 inches or a foot in length, may be 
entirely killed, the leaves, instead of dropping within a few days, 
turning brown and remaining attached to the dead twig. This is 
not necessarily accompanied by excessive shedding of the foliage. 
The physiological condition of the trees seems to have a marked 
effect on their liability to shed foliage, Vigorous trees are less 
susceptible than weak, poorly nourished ones. Trees in the same 
grove but growing under different conditions as regards the nature 
of the soil and the amount of soil moisture show r differences in this 
respect. In most groves trees will not shed leaves excessively if 
the dosage is increased 25 per cent above the recommended amounts. 
Frequently there will be no shedding at all following such a course. 
In other citrus groves the recommended dose is as large as the trees 
will stand without shedding to an injurious extent. 
The likelihood of damaging citrus fruits by fumigation is such that 
it is strongly advisable to pick the crop before starting to fumigate. 
In January, 1908, many seedling trees were fumigated which held 
from five to eight boxes of oranges per tree, without any injury 
whatever following the treatment. In other cases a small percent- 
age of the fruit developed sunken areas or "pits" which turned dark 
and ruined the affected fruit for shipping purposes. Fumigation 
in midwinter, using the dosage table given in the appendix, does not 
seem to affect the fruit of Hart's Lake, Lamb's Summer, or Valencia 
