Cacoecimorpha pronubana (Hübner, [1799]) and Epiphyas postvittana (Walker, 1863) are economically important polyphagous pest species. The larvae of these moths affect a wide range of horticultural crops. We evaluated the seasonal abundance and population dynamics of these two species, hypothesising that both species of moth exhibit similar patterns in their seasonal abundance and respond to abiotic factors. The study was carried out on a wide range of protected ornamental crops grown on a total area of 1 ha at a commercial nursery. The study was completed over five consecutive years from 2015 to 2019, where both populations were monitored weekly during the months of moth activity, from April to November, using sex pheromone traps to trap the males of both species. The timing and abundance of catches were analysed in relation to local meteorological data. The mean yearly abundance of adult males was 604 ± 23.89 (mean ± SE; C. pronubana) and 1706 ± 167.18 (E. postvittana) also differing significantly between years for both species. There was no influence of any weather measures on the abundance of E. postvittana, but sunshine duration (4.84 ± 0.26 hr) and temperature (13.04 ± 0.57°C) affected the mean seasonal abundance of C. pronubana. There was an overall difference in the seasonal pattern of abundance between the species studied. While we demonstrate a seasonal abundance difference between years for C. pronubana, we found no significant seasonal differences for E. postvittana. Improved understanding of seasonal abundance, phenological patterns and inter‐seasonal variations in population dynamics of these two species may be useful in developing forecasting models that can be used in improving integrated pest management strategies for these two pests.