diversity Article Cereal Straw Mulching in Strawberry—A Facilitator of Plant Visits by Edaphic Predatory Mites at Night? Fernanda de Cássia Neves Esteca 1,* , Nina Trandem 2,3, Ingeborg Klingen 3, Jandir Cruz Santos 4, Italo Delalibera Júnior 1 and Gilberto José de Moraes 1 1 Department of Entomology and Acarology, “Luiz de Queiroz” College of Agriculture (ESALQ), University of São Paulo (USP), Av. Pádua Dias, 11, Piracicaba SP 13418-900, Brazil;
[email protected] (I.D.J.);
[email protected] (G.J.d.M.) 2 Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway;
[email protected] 3 Biotechnology and Plant Health Division, Norwegian Institute of Bioeconomy Research (NIBIO), P.O. Box 115, 1431 Ås, Norway;
[email protected] 4 Centre for Biodiversity Genomics, 50 Stone Road East, University of Guelph, Guelph, ON N1G2W1, Canada;
[email protected] * Correspondence:
[email protected] Received: 3 May 2020; Accepted: 27 May 2020; Published: 13 June 2020 Abstract: In Norway, strawberry producers use cereal straw mulching to prevent berries from contacting the soil and to control weeds. We hypothesized that organic matter such as straw mulch also favors the maintenance of predatory mites which visit strawberry plants at nighttime. We compared mite diversity in cereal straw exposed for different periods in strawberry fields and evaluated their possible migration to plants in two experiments with potted plants in 2019. An ‘Early season’ experiment compared no mulching (T1), oat straw mulch exposed in field since 2018 (T2), or 2017 (T3), while a ‘Mid-season’ experiment compared no mulching (T1), barley straw mulch from 2018 (T2), or a mix from 2017 and 2018 (T3).