Why you need a mixture of two endoparasitic wasps including Aphidius colemani and Aphidius ervi. they can reduce the crop damage by parasitizing and killing a mixed population of a variety of host species of aphids that are responsible for the crop damage.
In the major cities of the Midwest and Northeast, they found relatively high paying jobs in meatpacking plants, shipyards, and steel mills. The second significant cause of the Great Migration was the desire of black Southerners to escape segregation, known euphemistically as Jim Crow.
Best Answer: The Great Migration was the massive relocation of blacks from the south to the north after the civil war. A really great book to read is James Grossman's Land of Hope.There are so many details about this migration that the book covers, more than I could ever type here.est Answer: The Great Migration was the massive relocation of blacks from the south to the north after the civil war. A really great book to read is James Grossman's Land of Hope.