Biodiversity and mite population fluctuation in different apple orchards in southern Brazil

Abstract

The aim of this work was to know the population fluctuation of the mites in apple (Malus domestica Borkh: Rosaceae) orchards with different crop management strategies, with emphasis on Aculus schlechtendali Nalepa (Eriophyidae) and Panonychus ulmi (Koch) (Tetranychidae) and their natural enemies. The studies were carried out in 2020-21, in three organic orchards (Eva, Fuji and Gala), from Antônio Prado, two conventional (Fuji and Gala), from Muitos Capões, RS, Brazil, and two of regenerative agriculture (Fuji and Gala), in São Joaquim, SC, Brazil. Forty plants/orchard were sampled, from which three leaves/plant from the apical, median and basal offshoot were detached. The material was screened and identified in the laboratory. A total of 7.193 specimens, belonging to 14 families, 29 genera, and 40 species, were collected. The most common phytophagous mites were A. schlechtendali (46.2%), P. ulmi (16.9%) and Polyphagotarsonemus latus Banks (Tarsonemidae) (10.9%). Panonychus ulmi was observed in all orchards, being abundant in conventional and regenerative orchards. The most common predatory mites were Neoseiulus californicus (McGregor) (Phytoseiidae), Agistemus riograndensis Johann and Ferla (Stigmaeidae) and Agistemus brasiliensis Matioli, Ueckermann and Oliveira (Stigmaeidae). Among predators, greater diversity was observed in organic orchards, while in conventional and regenerative orchards N. californicus was the most common. Greater acarine abundance was observed when there was an increase in temperatures, and the predatory mites increased their populations in response to the presence of phytophagous mites. The results suggest that the mite populations were influenced by the cultivar and mainly by the management used.