What is the difference between saprotrophic …

In parasitic mode of nutrition, plants depend on other live plants or animals for their nourishment. Such plants are called as parasites and the ones on which parasites depend are called as hosts. 
The insectivorous mode of nutrition is observed in plants like pitcher plant and the Venus fly trap. They purely depend on other insects and small animals for their nutrition. Cuscuta is a parasitic plant which develops special roots called haustoria. Haustoria penetrate deep into host plant tissues and just absorb the nutrients from them.
 
The plants which exhibit saprotrophic mode of nutrition are called as saprotrophs. Saprotrophs are the plants that obtain their nutrition from dead and decaying organic matter. Saprotrophs secrete digestive juices onto dead and decaying matter to dissolve it and then absorb nutrients from it.