Feasibility and efficacy of a new approach for controlling populations of the rosy apple aphid, Dysaphis plantaginea Passerini (Hemiptera: Aphididae) in south-eastern France

ABSTRACT

Episyrphus balteatus De Geer (Diptera: Syrphidae) is one of the most efficient biocontrol agents against Dysaphis plantaginea Passerini (Hemiptera: Aphididae) in apple orchards due to its early arrival. However, releasing flying predators in open orchards may be risky. We thus evaluated the combined effects of biological (early release of syrphids) and physical (Alt'Carpo nets) methods for controlling aphids under orchard conditions assuming that syrphids released under the nets will be able to survive and reproduce. Five experimental treatments containing two rows of trees each were set up in a pesticide-free orchard containing two different apple cultivars. For each cultivar, E. Balteatus adults were released (25, 40 and 90 adults per row) into three treatments, which were covered with nets, and two treatments were maintained free as controls (with and without nets). The releases, mainly in treatment 90, had a small effect on the development of the aphid population compared to netted control trees, especially towards the end of the study period when some of the differences were significant. This study demonstrated that E. balteatus adults can be successfully released under nets since we did observe an accumulation in the offspring of released individuals, mainly in treatments 40 and 90.

KEYWORDS:

• Biological control
• augmentation
• physical control
• Episyrphus balteatus
• Alt'Carpo nets
• IPM

Acknowledgments

We are grateful to Anne-Marie Lacordaire (Koppert Company) for providing syrphid pupae. We would like to thank Odile Mascle for technical assistance. We thank also Jean-Pierre Sarthou and Jean-Pierre Jansen for helpful scientific advice.

Disclosure statement

No potential conflict of interest was reported by the authors.