414 
lighter frosts have touched them. The 
advancement or retardation of the buds 
may account for this. Though neither 
the pistil nor the stamens are badly in- 
jured by the frost, the ovary may be so 
badly injured that fecundation is impos- 
sible. Heavy frosts during the blossom- 
ing period may so impair the fruiting 
organs as to cause the dropping of the 
fruits after they have set. 
4. The trees may lack proper nour- 
ishment.—This may be from a lack of 
water or it may be from a lack of other 
plant foods. Orchards which have been 
improperly cultivated, or which have 
grown heavy crops of apples and have 
not had the elements removed by 
these crops returned, may fail to set 
fruit buds in the proper manner. In an 
experiment with pollen from an improp- 
erly nourished Missouri Pippin, it was 
found that this pollen was very much 
less potent than the pollen from a more 
thrifty tree. Poorly nourished trees were 
found to be more liable to self-sterility. 
Many orchards set in the early history 
of the different sections have ceased 
bearing, in all probability from the 
effects of continued starvation, and many 
other younger orchards fail to set fruit 
from the same cause. 
5b. The trees may fail to set fruit 
from an excess of certain kinds of nour- 
ishment—The above may be the case or 
they may have plant food at the wrong 
season of the year. It is a well known 
fact that the reproductive and the vege- 
tative powers of a tree are exercised in 
direct opposition to each other, and a 
tree making too great a vegetative 
growth is liable to be barren. This is 
especially true of orchards planted close 
to barns, feed-lots or corrals, where the 
owner is in the habit of dumping ma- 
nures. Under such favorable conditions 
to the development of the vegetative 
portion of a tree, it would be much 
longer in reaching maturity and would 
never bear as well as another tree plant- 
ed in soil with nearer the optimum 
amount of plant food or with plant food 
better adapted to its needs. On such a 
tree the fruit buds would be few and 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
would go into winter in an immature 
condition, with few chances of escaping 
winter injury. Orchards may fail to set 
fruit because of too great a growth dur. 
ing the season when fruit buds are form. 
ing. A later fall growth may open the 
road to winter injury because of im- 
proper ripening of the wood. Winter 
killing of the immature wood, together 
with the fruit buds, is very often the 
result. 
6. Blossoms may fail to set fruit from 
improper pollination—Though the trees 
may be in perfect health, the winter may 
not have been severe and the orchard 
may be a mass of bloom, there may be 
only a fraction of a crop Isolated trees 
which are self-sterile cannot set a full 
crop of fruit because so few bees, the 
only agents of pollination acting at a 
distance, visit two trees very far apart 
during the same absence from the hive, 
and very few of the blossoms would thus 
be fertilized. The same would be true 
of large blocks of trees planted to single 
varieties. The bees would carry little 
else than the pollen of that variety. An- 
other case of improper pollination is 
noticed when the weather is damp and 
cold during the blossoming period. Such 
weather prevents the work of bees and 
often causes the germination or the 
decomposition of the pollen grains. Even 
when the pollen grains are not entirely 
spoiled, may it not happen that when 
slightly wet pollen falls on the stigma 
it possesses just enough vitality to ger- 
minate and start fecundation, but not 
enough to carry it through all the 
changes necessary to complete fertiliza- 
tion? If such be the case, the pistil 
after responding would waste away. 
Vigorous pollen would thus be prevented 
from fertilizing the pistil, when the 
weather became bright and warm enough 
to properly ripen the pollen and bring 
out the bees, and fruit would fail to set 
as it should. 
Dry, hot and windy weather may so 
badly injure the stamens that they can- 
not properly mature their pollen or it 
may cause the dehiscence of the anthers 
before the pollen is mature. The same 
