The objective of this study was to determine the damage levels caused by Orthezia praelonga Douglas, 1891 and Leucoptera coffeella (Guérin-Mèneville 1842), on rangpur lime and Obatã coffee leaves, respectively. Measurements were based on a new concept for the evaluation of the following plant physiological parameters: photosynthesis, stomatal conductance, leaf temperature and transpiration, and internal concentration of CO2 (by infrared analyzer). A negative correlation between infestation level and photosynthesis was found, where the negative inflexion point of the curve was considered as a reference for damage levels. The control level for O. praelonga is below the 7-13% limit for damaged leaf area (40 to 70 scales per leaf), while for L. coffeella it is below the 26-36% limit for the same variable. Photosynthesis provided the best correlation for this type of analysis.
photosynthesis; economic level injury; citrus; coffee; plant-insect interactions
