500
Read the passage then answer the question.
The summer of 1874 was hot and humid on the Great Plains of the United States. In late August, as farmers were getting ready to harvest their crops, the sky suddenly darkened. But it was not a sudden storm. Clouds of grasshoppers, millions of them, were swarming onto the Great Plains. They stripped the trees bare and destroyed millions of acres of wheat and corn. They even stalled trains! The crushed bodies of the insects made the tracks so slippery that the wheels of many locomotives spun helplessly on the tracks.
Grasshoppers also invaded homes. Frantic family members attacked them with brooms, mops, and dustpans, but the plague of insects got into anything that was not tightly sealed. Many people in the hardest-hit areas couldn't raise the cover off a pan on the stove without grasshoppers jumping into it. Settlers used fire and smoke to try and destroy the insects, but nothing seemed to help very much. Every summer from 1874 through 1877, millions of grasshoppers swept across North and South Dakota, Nebraska, Kansas, Oklahoma, and parts of Texas.
What is the main idea of this selection?
From 1874-1877, millions of grasshoppers invaded the Great Plains that destroyed crops, hindered travel and transportation, and invaded homes.