Today, plant parasitic nematodes are successfully controlled by nematicides. Now, nematicides are losing their popularity among farmers for protecting their crops from nematode infestations. As for nematologists, resistance induction for susceptible plants to nematode infestation through the addition of certain components to callus or root explants in tissue culture medium has not yet undertaken. In recent years, there has been an increased interest in the application of antioxidants, vitamins, amino acids, mineral salts, growth hormones and natural products to medicinal and agricultural treatments. This book therefore, assess the impact of growth medium supplemented with essential oils or antioxidants or vitamins or natural products on tomato tolerance to infection with M. incognita or P. penetrans, the nematicidal activity of methanolic callus extracts derived from Nerium oleander against M. incognita or P. penetrans in-vitro, and the nematicidal activity of callus dried powders derived from certain plants against M. incognita infesting tomato plants under field conditions.