Seasonal dynamics of the cabbage armyworm (Mamestra brassicae [L.]) and the bright-line brown-eyes moth (Mamestra oleracea [L.]) in Slovenia

Abstract

The cabbage armyworm (Mamestra brassicae L.) and the bright-line brown-eyes moth (Mamestra oleracea L.) are polyphagous insect species. From 2008 to 2010, we monitored the seasonal dynamics of both pests in two locations in Slovenia, Ljubljana and the Nova Gorica region. Pheromone traps (VARL + type) were used to precisely determine the occurrence of adults, i.e., the beginning and end of generations and the peaks of the populations. This allowed us to examine the relationship between the quantity of pests, average daily air temperature and average daily precipitation. Our results established that there were two generations of Mamestra brassicae per year in both locations; however, the seasonal dynamics of Mamestra oleracea was not as clear due to low trap catch. During 2008–2010 in Ljubljana, the average temperature during the peaks of the first generation of M. brassicae ranged from 16–19°C (sum of effective temperatures (SET) from 250°C to 375°C) and 20°C (SET from 986°C to 1,290°C) during the peaks of the second generation. We found no correlation between the average number of cabbage armyworm adults during the peaks of both generations and the mean air temperature 35 and 70 days prior to the peaks.