Why can the unification of the northern and southern parts of Egypt be described as the "greatest event in ancient Egyptian political history"?

In 1914, alabama produced 1.7 million bales of cotton, but three years later produced only 515,000, bales. meanwhile, in georgia, 5.2 million acres of land was dedicated for cotton production in 1914, but by 1923 there were just 2.6 million acres used for growing cotton. all of this was the result of the work of a tiny insect: the boll weevil. alabama and georgia first felt the effects of the boll weevil at different times. what would account for this difference in timing?