The good, the bad and the ugly: are beneficial mites threatened in apple orchards due to climate change and pesticides?
Abstract
The Green Deal of the EU includes two essential objectives: the reduction of pesticide applications and the conservation and restoration of biodiversity. Pesticide reductions are expected to increase the diversity and abundance of natural enemies of pests and consequently also their biocontrol success. However, the vast majority of natural enemies are arthropods, and their diversity strongly declined in the last decades at a global scale. Among other stressors, climate warming is a major driver responsible for the decline of arthropods. In agroecosystems, arthropods are also confronted with a second stressor: agricultural intensification, defined as the increase of agricultural productivity per unit area. Although these two factors are known to be tightly linked, they are usually analyzed separately. However, they may interact additively or synergistically boosting the negative consequences on arthropod diversity in agroecosystems. Apple is the most dominant fruit species in Austria. A serious pest mite, the red spider mite Panonychus ulmi, was efficiently controlled by predatory mites as natural enemies in the past, but regained nowadays the status of a main pest in Styrian apple orchards. Our main hypotheses for this project are: (i) climate warming reduces mite diversity; (ii) synergistic effects between climate warming and agricultural intensification (e.g. pesticide applications) enhance the negative effects on mite diversity; and finally (iii) the natural enemies (i.e. predatory mites) suffer more from the two stressors compared to their prey (i.e. pest mites), which lead to insufficient biocontrol of pest mites. First, we will sample mites in integrated, organic orchards and extensively managed apple meadow orchards (i.e. no pesticide and fertilizer applications) in Styria during two growing seasons, which allow the evaluation of climate warming and agricultural intensification effects on mite diversity. Additionally, mite diversity in extensively managed meadow orchards will be compared between 1985 (historical mite data are available) and 2024/25, to evaluate only climate warming effects on mite diversity. Second, climate warming may indirectly influence mite diversity via promoting agricultural intensification. For example, the use of fungicides in apple orchards increased because of apple scab incidences in the last two decades in Austria, and predatory mites are known to be highly sensitive to fungicides. Thus, micro-climatic data from apple orchards (1961-2025) will be integrated in a dynamic forecast model for apple scab to evaluate, whether climate warming effects could be a potential driver for higher incidences of apple scab indicating synergistic effects between climate warming and agricultural intensification on mite diversity.
keywords climate warming agricultural intensification biodiversity mites apple orchards
Publikationen
Project staff
Andreas Walzer
Mag. Dr. Andreas Walzer
andreas.walzer@boku.ac.at
Tel: +43 1 47654-95308
Project Leader
03.07.2023 - 02.07.2026
Herbert Formayer
Assoc. Prof. Priv.-Doz. Mag. Dr. Herbert Formayer
herbert.formayer@boku.ac.at
Tel: +43 1 47654-81415
Project Staff
03.07.2023 - 11.07.2023
Tatiana Klisho
Tatiana Klisho MSc.
tatiana.klisho@boku.ac.at
Tel: +43 1 47654-81413
Project Staff
03.07.2023 - 02.07.2026
Stefan Möth
Dipl.-Ing. Dr.rer.nat. Stefan Möth
stefan.moeth@boku.ac.at
Tel: +43 1 47654-95329
Project Staff
03.07.2023 - 02.07.2026
Bernhard Spangl
Dipl.-Ing. Dr. Bernhard Spangl
bernhard.spangl@boku.ac.at
Tel: +43 1 47654-85113
Project Staff
03.07.2023 - 02.07.2026
Sabina Thaler
Mag. Mag. Dr. Sabina Thaler
sabina.thaler@boku.ac.at
Tel: +43 1 47654-81420
Project Staff
03.07.2023 - 02.07.2026
Silvia Winter
Dipl.-Ing. Dr.nat.techn. Silvia Winter
silvia.winter@boku.ac.at
Tel: +43 1 47654-95307
Project Staff
03.07.2023 - 02.07.2026
BOKU partners
External partners
University of Extremadura
Dr. Daniel Paredes
partner
University of Montpellier, INRA,CIRAD
Dr. Marie-Stephane Tixier
partner
Universidad de Málaga- Consejo Superior de Investigaciones Científicas, Málaga,_x000D_ Spain
Dr. Marta Montserrat
partner