Complex of Aphidophagous Predators of Mealy Plum Aphid Hyalopterus pruni Geoffr. and Their Efficiency in Pest Control †.

Aphids are the dominant pests in the complex of harmful fauna of stone fruits in Ukraine. In plum orchards mealy plum aphid Hyalopterus pruni Geoffr. (Hemiptera: Aphidinae) causes serious economic damage. Insect predators have an important role in the regulation of agricultural pests. Our goal was to determine the role of predation in the dynamics of the mealy-plum-aphid population. Investigations were carried out during the period of mass development of the mealy plum aphid in the experimental plum-orchard garden of the Institute of Horticulture of the National Academy of Agrarian Sciences of Ukraine. For this purpose, model trees were selected and isolators were installed on four branches of each tree with aphid-infested leaves. Different species of entomophagous predators were placed in the isolators and assessments were performed on a daily basis. According to our observations, Adalia bipunctata L., A. decempunctata L., Syrphus ribesii L., S. balteatus Deg, Chrysopa perla L., and Ch. carnea Steph. dominated among aphidophagous predators. Coccinella septempunctata L., Calvia quatuordecimguttata L., and Propylaea quatuordecimpunctata L. were less common. Syrphus and Chrysopa larvae had the highest predation activity. The influence of weather conditions on the efficiency of aphidophagous predators was analyzed. Optimal conditions for A. bipunctata, A. decempunctata, S. ribesii, S. balteatus, Ch. perla, and Ch. carnea during June–July were as follows: mean daily temperature, 17–20 °C, precipitation 0.1–1.5 mm, and relative air humidity 57–67%. The threshold ratios of dominant aphidophagous predators were determined. The high predation activity of Syrphus and Chrysopa larvae and coccinellids indicated that the ratio of entomophages to aphids must be taken into account when making decisions about control measures [ABSTRACT FROM AUTHOR]