Impact of Shelterbelts on the Diversity and Dynamics of Natural Enemies in Wheat Agroecosystems

Biological and integrated pest management strategies have recently been widely adopted in crop protection, with one of the key approaches involving the use of natural enemies (predators and parasites). In order to identify and monitor beneficial arthropod species associated with winter wheat crops, an experiment was conducted between 2022 and 2024 in two locations in the Transylvanian Plateau: Turda, within an open-field agroecosystem, and Bolduţ, within an agroecosystem with protective agroforestry shelterbelts. The research aimed to evaluate the diversity of beneficial arthropod fauna in two agroecosystems, as well as the impact of insecticide treatments on the natural enemies of wheat pests. According to our findings, it can be stated that the beneficial arthropods identified in the two agroecosystems belonging to the same groups, but the abundance in all three years is higher in the agroecosystem with agroforestry shelterbelts. Among all the analyzed arthropods, the order Araneae was characterized by the highest abundance, recording 995 individuals in an insecticide-free variant in 2022. The treated variants with insecticide showed a decrease in both abundance and diversity in agroecosystems with and without shelterbelts during all three experimental years, compared to the variant without insecticides. Regarding abundance, the largest difference was recorded in 2024 in the shelterbelt agroecosystem with a reduction of 781 individuals. In terms of diversity, the lowest value was observed for the Shannon_H index in open-field agroecosystem in 2024 for the variant treated with insecticides (1.426), compared to the untreated variant, where the index reached a value of 1.841. The application of insecticide treatments caused an increase in the mortality of beneficial arthropods, reaching its highest level in 2024.