Control of Root Knot Nematode (M. incognita ) via Improve Defense Ability by Using Salicylic Acid in Eggplant (Solanum melongena)

Abstract

Effect of salicylic acid (SA) as chemical resistance inducer against root knot nematode M. incognita (RKN) on eggplant was investigated during 2022-2023 growing season. Five salicylic acid concentrations 100, 150, 200, 250 and 300 uM as seedling roots dipping solutions. Studied treatments significantly (P≤0.05) reduced root -knot nematode parameters compare to control treatment. Highest significant effects were achieved under using of 300 uM treatment which caused reduction percentages of 68.83 %and 69.09 % for final population (Pf) and reproductive factor (RF) lower than control treatment, respectively. Antioxidant enzymes and antioxidant compounds showed significant effects in eggplant infected with (RKN). Activity of peroxidase, polyphenoloxidase and catalase antioxidant enzymes were increased as a result of SA treatments with the highest significantly effects of 300 uM treatments. Total and free phenols and total chlorophyll (a+b) contents in SA treating plants were significantly increased compare to control treatment. Carotenoids and free amino acids contents were increased with salicylic acid application while proline contents were decreased. All studied SA treatments significantly increased eggplant growth attributes i.e. shoot and root fresh weights, dry shoot weight, shoot and root lengths with the highest effects at 300 uM treatment, compare to control plants. It seems that SA at 300 uM concentration seedling roots dipping solutions as an abiotic resistance inducer treatment could be used to control root-knot M. incognita on eggplant by decreasing both cost and hazard effects of chemical nematicides.