Labor in the southern colonies was in high demand because of what

Labor was at a high demand and the tasks required were difficult and menial there was a high demand for slave labor. Slave labor served as a major factor with crops like cotton. 

Slaves were in high demand in the southern colonies because the major industry in the south was agriculture that required a large amount of labor. Because labor was at a high demand and the tasks required were difficult and menial there was a high demand for slave labor. Slave labor served as a major factor in establishing the South as an agricultural hub during this period especially with crops like cotton.