Leaves of cotton plants with "leaf burn" symptoms in untreated plots had higher leaf temperature, higher leaf water potentials, lower transpiration rates and reduced photosynthetic rates as compared to leaves of cotton plants without "leaf burn" symptoms in Temik^®-treated plots. Leaves of cotton plants in untreated control plots exhibited higher leaf temperatures prior to the occurrence of visual "leaf burn" symptoms than leaves of Temik-treated cotton plants also without "leaf burn" symptoms. Leaf water potential and transpiration rates were, in general, also affected prior to visual "leaf burn" symptoms. Photosynthetic rates of leaves on plants in Temik-treated plots without "leaf burn" symptoms was higher than in leaves with "leaf burn" symptoms on plants in untreated plots.Cotton lint yields from plants in untreated controls with "leaf burn" symptoms were significantly reduced as compared to lint yields from Temik-treated plots that did not show "leaf burn" symptoms.