Effect of mating disruption technique, at the rate of 300 PB-Rope dispensers/feddan for suppressing the population and percentage of infestation with the pink bollworm (PBW), Pectinophora gossypiella
(Saunders) was investigated in cotton fields at Assuit Governorate (Upper Egypt), throughout the two successive cotton growing seasons 2013-2014. Catches of PBW moths in the sex pheromone traps and the damage in green bolls were recorded in both treated and control fields. Data showed that moth catches were highly suppressed (near 100%) in the treated field by installation of the dispensers during the 50% flowering growth stage. In addition, % of average infestation in the cotton green bolls was significantly decreased in the treated (1.51&0.89) compared with the control field (20.54 &12.33%) in both seasons, respectively. A significant difference was found in the average yield/feddan estimated at the plot treated with pheromones (10.25 Kent.) compared with the control (6.37 Kent.). This study recommended using only one application of pheromone dispenser during the flowering growth stage of the cotton plants is sufficient to maintain the moth catches and infestation % in green bolls at the lowest level.