Abstract: This paper quantitatively describes the changes of chlorophyll content and leaf area loss of cotton plants infested by the mite. Dynamic models of leaf area loss are also established. The conception of "efficient leaf area" is put forward, representing the part of un-infested leaf area, which may be refered to research the leaf area loss of crops infested by other insect pests.

Key words: cutting, burning, Alhagi sparsifolia, morphological characteristics, aboveground biomass