Weathering is a process of physical disintegration of the rocks or other materials present over the earth crust into small particles or sediments due to a physical agent such as water or wind. The erosion is the process of mechanical or physical removal of the top layer of the soil or any surface material and transportation of the material to the other location. Mass wasting is the process in which unstable materials get dislocate from their place due to the effect of gravity.
Erosion is caused by the combination of physical factors like wind, water and gravity.
Pesticide use can be very harmful beacause too much of them can cause the crops to go bad, and kill bees which help spread pollen and enhance the crops.