Effect of Jasmonic Acid on Chlorophyll Content in Wheat (Triticum aestivum L.) Plants Infested with Russian Wheat Aphid (Diuraphis noxia)

Russian wheat aphid (Diuraphis noxia Homoptera; Aphididae) is a major pest that significantly reduces chlorophyll content and photosynthetic capacity in wheat (Triticum aestivum L.), leading to substantial crop yield losses. Jasmonic acid (JA) is a plant signaling molecule known to activate defense mechanisms against herbivorous insects. This study examined the effectiveness of exogenous jasmonic acid application in maintaining chlorophyll content during Russian wheat aphid infestation. A pot experiment was conducted with four treatments: control (no treatment), aphid infestation only, jasmonic acid application only, and jasmonic acid with aphid infestation. Results demonstrated that aphid infestation significantly reduced chlorophyll a (F = 42.565, P = 0.0001), chlorophyll b (F = 52.565, P = 0.0001), and total chlorophyll (F = 32.565, P = 0.0002) contents compared to healthy plants. Jasmonic acid treatment at 2 mM concentration effectively preserved all forms of chlorophyll, significantly counteracting aphid-induced chlorophyll depletion (P < 0.01). The protective effect of jasmonic acid was evident through the statistically significant interaction between aphid stress and JA application for all chlorophyll parameters. These findings suggest that foliar application of jasmonic acid can serve as an effective strategy to maintain photosynthetic capacity and plant vigor under Russian wheat aphid attack, thereby contributing to sustainable crop management and improved wheat production.