Gall-induced stress in the leaves of Terminalia arjuna, food plant of tropical tasar silkworm, Antheraea mylitta

Tasar silkworm Antheraea mylitta Drury is reared on one of the important food plants, Terminalia arjuna (Arjun). Leaf gall Trioza fletcheri minor (Hemiptera: Psyllidae) is the most important gall forming insect on the leaves which has bearing on productive traits of tasar silkworm. Gall formation is the consequence of interaction between the offensive stimulus of the insect and the defensive response of the plant. Hence, the stress on Arjun leaves imparted due to gall formation was studied. There was significant decrease in photosynthesis rate (P<0.001), transpiration rate (P<0.05) and stomatal conductance (P<0.05) in gall infested leaves in comparison to healthy ones while no change in leaf temperature. The oxidative stress assayed through lipid peroxidation and hydrogen peroxide production was found to be significantly higher (P<0.001) in gall infested leaves than that of healthy ones. Non-enzymatic anti-oxidant, ascorbic acid content was found to be high in gall leaves while there was decrease in reduced glutathione content (P<0.01). The total protein and moisture content values were recorded to be higher in gall infected leaves (P<0.01) than the healthy ones indicating towards nutrient flux for the gall insect.