Sex pheromone‐baited traps were used to monitor populations ofPrays oleae(Bern) in an olive grove near Granada, Spain, eyery year from 1979 to 1987 during the flight of adults that gives rise to the larvae of the fruit generation. Attempts at establishing a correlation between the catches of adult P.oleaein sex pheromone baited traps and subsequent fruit infestations were successful in each year separately, but not when the data for all yearswerecombined. However, when account was taken of the degree of synchrony between adult emergence and the stage of development of the fruit, from the point of view of suitability for oviposition as perceived by the females, good correlations could be obtained. A very high coefficient was therefore obtained when fruit infestation was correlated with accumulated adult catches from the date of commencement of oviposition. The practical applications of the findings are discussed.