Effect of Silicon and Salicylic Acid in Biochemical Defence Mechanisms of Santa Teriza Lemon Trees to Reduce Citrus Leaf Miner Damage

Ahmad, B., S. Suleiman and M. Ahmad. 2024. Effect of Silicon and Salicylic Acid in Biochemical Defence Mechanisms of Santa Teriza Lemon Trees to Reduce Citrus Leaf Miner Damage. Arab Journal of Plant Protection, 42(1): 67-74. https://doi.org/10.22268/AJPP-001208 The effect of foliar spray of young lemon trees (Santa Teresa) with silicon (200-400 ppm) and salicylic acid (50-75ppm), on antioxidant enzymes activities (catalase CAT), H2O2 content, total chlorophyll, α-free amino acids, leaf thickness and their influence on leaf miner (Phyllocnistis citrella) biology (pupa length and oviposition) under field condition was investigated. The results obtained indicated that treatment with silicon and salicylic acid reduced biotic stress due to citrus leaf miner on the Santa Teresa Lime trees, leaf content of H2O2 (0.4 2-0.43 nmol g-1 FW), catalase activity were decreased (0.213 – 0.211 mmol/ min/g fresh weight), There was an increase in α-free amino acids content (45.3-40.2 μg/g fresh weight), total chlorophyll (41.52-35.17 spad) and leaf thickness (2.1-1.3 mm), and these changes were clearly manifested in the biology of citrus leaf miner in vivo, such as reduction in pupa length (2.10-2.20 mm), and the average number of eggs (8.7- 10.7 eggs). Such results are promising for the control of citrus leaf miner without using pesticides. Keywords: Silicon, salicylic acid, Santa Teresa lime, antioxidant enzyme (CAT), H2O2 content, total chlorophyll, α-free amino acids, leaf thickness, citrus leaf miner