Biotic factors are more important than abiotic factors in regulating the abundance of Plutella xylostella L., in Southern Brazil

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• 作者：Cesar Augusto Marchioro^a ; ^{c.marchioro@ufsc.br" class="auth_mail" title="E-mail the corresponding author} ; Luí ; s Amilton Foerster^b
• 关键词：Apanteles piceotrichosus ; Diadegma leontiniae ; Oomyzus sokolowskii ; Parasitism level ; Siphona sp.
• 刊名：Revista Brasileira de Entomologia
• 出版年：2016
• 出版时间：October-December 2016
• 年：2016
• 卷：60
• 期：4
• 页码：328-333
• 全文大小：701 K

文摘

The serious economic loss caused m>Plutella xylostellam> L., 1758 in several regions of the world has prompted a demand for alternative management strategies. In this context, understanding the key factors governing the population dynamics of the pest is important for development of management strategies. This study aimed to identify the larval parasitoids associated with m>P. xylostellam> and investigate the biotic (crop subspecies, plant age and parasitism) and abiotic factors (minimum and maximum temperatures, rainfall, relative humidity and planting season) affecting the population dynamics of the pest in organic crops located in Southern Paraná State, Brazil. Despite the continuous and abundant availability of host plants throughout the year, m>P. xylostellam> occurred between June and November, and the largest peaks of abundance were observed between August and September, when low temperatures and rainfall were recorded. According to the stepwise regression analysis, m>P. xylostellam> was more abundant in broccoli during winter. Neither temperature, nor rainfall significantly influenced pest abundance. Four species of larval parasitoids were identified associated with the pest, of which m>Diadegma leontiniaem> (Brèthes) (Hymenoptera: Ichneumonidae), m>Apanteles piceotrichosusm> Blanchard (Hymenoptera: Braconidae) and m>Siphonam> sp. Meigen (Diptera: Tachinidae) were abundant, while m>Oomyzus sokolowskiim> (Kurdjumov) (Hymenoptera: Eulophidae) was rarely found. Parasitism was the major factor influencing population dynamics of m>P. xylostellam>, contributing to 48% of the variation in pest abundance. These results show the importance of larval parasitoids complex in regulating m>P. xylostellam> population and that the temperature and rainfall recorded during field experiments did not influenced pest abundance.