CHAPTER II.
COTTON-PLANT DISEASES AND PESTS.
There are several classes of agents all of which act injuriously more or less on the Cotton plant.
1. Climatic changes, including hygrometric variations of the atmosphere, and extremes of 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.