Aphids (Hemiptera: Aphididae) on Alfalfa and and their Coccinellid Predators in Serbia: Seasonal Abundance

Abstract

Population dynamics and flight activity of alfalfa aphids were documented at two locations in Serbia in 2011 and 2012. Additionally, the abundance of coccinellid predators was tested for correlation with aphid abundance. In order to verify the potential presence of the invasive Acyrthosiphon kondoi, aphids were collected from 44 alfalfa fields. Two sampling methods were used: stem samples and water traps. There were two seasonal peaks for aphids and coccinellids during both years, the end of May and the end of August. The most abundant aphid species was Therioaphis trifolii. Eight aphidophagous coccinellids were recorded. The invasive Harmonia axyridis (Pallas) was one of the three most abundant coccinellids. Pearson's product-moment correlation showed a significant correlation of coccinellid predators associated with aphids on alfalfa. Pearson's product-moment correlation between the number of aphids on alfalfa stem and in traps was found significant only for T trifolii, which was the most numerous species in the traps. More Aphis craccivora were collected with water traps as compared to alfalfa stems, whereas more Acyrthosiphon pisum specimens were collected from alfalfa stems than from traps. The invasive species A. kondoi was not recorded in Serbia during this study.