f heat and cold.

2. Insect pests.

3. Physiological diseases of the plant.

4. Blights caused by fungi.

It has been pointed out in the early pages of this story, how very
sensible to changes of heat and cold, the Cotton plant is, especially in
the early growing period. When the plant has just risen above the
ground, and is beginning to spread its roots, too great an amount of
heat would be fatal to its further growth.

Instances could be given where very serious decreases in the production
of cotton in the States especially have taken place, due entirely to
unusually high temperatures which obtained during the early growing
period of the Cotton plant.

Extremes of frost are likewise fatal to the growth of the young plant.
By the beginning of April, frosts have as a rule disappeared, and no
further fear need be felt on that account, though if the end of winter
has been abnormally warm, and the young plants have been making leaf too
quickly, it will be readily seen how fatal a sharp frost or two must be
to the young and tender plant. There are cases, however, when a frost
is beneficial.

Then again, while rain is needed in fair quantity, too much of it is
followed by rot and myriads of pests. If the planter desires anything at
all when his crop is ripe, it is fine weather in which to gather his
harvest.

Frequently large quantities of cotton are left on the plantations,
because it is too wet to gather it. This happened a few years ago to an
unusual extent, when a vast quantity of cotton had to be left upon the
fields.

Of all the injurious agents most dreaded in the cotton-growing districts
of the globe, none are so widely spread or so disastrous as "insect
pests."

They attack different parts of the plant during its growth, and when the
bolls are formed they commit great havoc among these by boring through
and completely ruining the immature fibre. Then again, while the plant
is young, they may attack the most tender portion of the plant, viz.,
the new and young leaves found at or near the top. This they soon clear
and make their way as caterpillars down the plant, and they frequently
clear it as though the leaves had been plucked off.

So completely do they do their work that it has been calculated in
certain years the loss on this account alone cannot have been far short
in America of 3-1/2 million pounds in one year.

Of the chief forms of insect pests, two specially stand out into