Developing a relationship between pest abundance and damage to crops is essential for the calculation of economic injury levels (EILs) and to anticipate informed management decisions. Field studies were conducted for three successive years (2005, 2006 and 2007) in peach orchards of northern Greece to examine relationships between densities of Anarsia lineatella Zeller (Lepidoptera: Gelechiidae) populations and peach (Prunus persica) yields. According to a linear regression model, the increase in moth’s densities during the 1st flight resulted in a significant reduction in yield (y = 0.436x + 10.22, R2 = 0.635, d.f. = 2,11, P < 0.05). Correlation of male moths captured during the 2nd flight and observed yield loss was significant (y = 0.5231x + 17.204, R2 = 0.792, d.f. = 2,11, P < 0.05). Moreover, according to a linear model by counting the number of shoot strikes, during the first observation period, a forthcoming yield loss can be estimated (y = 27.389x−6.304, R2 = 0.711, d.f. 2,11, F = 22.09, P < 0.05). A significant relationship was observed between the numbers of the 2nd generation larvae and yield loss (y = 163x, R2 = 0.890). Regression coefficient of the above function represents yield loss per pest and was applied in the calculation of EIL’s and fixed Economic thresholds (ET’s). In addition, parameter of the price commodity was estimated for 2009 by applying stochastic autoregressive moving average model. By integrating above information, EIL and fixed ET estimated as 112 larvae and 84 larvae per sampling unit for a mean value (€4/0.1 ha) of cost management tactics and a 90% efficacy.