Abstract
The gas exchange capacity responses of cucumber Cucumis sativus L. under several infestation intensities of leafminer Liriomyza trifolii (Burgess) were determined under greenhouse conditions in the eastern province of Saudi Arabia. Two levels of leafminer infestation were used, light and severe beside healthy plants as control. Yield of cucumber fruits was significantly reduced as leafminer infestation increased. Net photosynthesis rate in the mined part of leaves was significantly reduced under light and severe infestation, compared with the control. This reduction was substantial under severe infestation conditions. The reduction in net photosynthesis rate was found to be correlated with the reduction in mesophyll conductance of the mined area of leaves under light and severe infestation and also in undamaged parts of severe infestation. Chlorophyll content was reduced significantly with increasing infestation intensity. Intercellular CO2 concentration was increased with increasing infestation intensity.