Mohammad Modarresi

Exogenous application of jasmonic acid (JA) can trigger the induced resistance of plants to herbivores. This study aimed to investigate the genetic variation of 13 cucumber cultivars in response to the exogenous application of JA for inducing resistance to the vegetable leafminer, Liriomyza sativae, in the feld. The plants were treated with 0 (control), 10, or 50 μM of JA and exposed to natural infestation by L. sativae. Exogenous application of JA-induced resistance to L. sativae, but its efects varied across the cultivars. The most prominent decrease in plant damage (34.7%), leaf damage (78.2%), and the number of larval mines (58%) were observed in Argeto, 14cu4141, and Aroma with 50 μM JA, respectively. The plants sprayed with JA had more leaf thickness, trichome density, and phenol content compared to control plants. Soheil and Beit Alpha2 had the greatest increase in leaf thickness (89.50%) and trichome density (74.42%) at 10 μM JA, respectively. The highest increase of phenol content (14.70%) was seen in Emparator upon treatment with 50 μM JA. Insect damage showed signifcant negative correlations with leaf thickness and phenol content. Our results indicate that crop cultivars that respond better to treatment should be determined to use JA in pest management programs.