Abstract The diamondback moth (DBM), Plutella xylostella L. (Lepidoptera: Plutellidae), is the most destructive pest of brassicas worldwide. Cultural control of this pest is important due to the reported resistance of DBM strains to most insecticides and should be devised from basic information related to the pest. This study investigated the influence of the host plant and climate in the seasonal dynamics of the DBM and the within-plant distribution of DBM in the most cultivated cole crops in Southeast Brazil (broccoli, cabbage, and cauliflower). Broccoli and cauliflower presented the highest and lowest DBM abundances, respectively. Temperature and relative humidity were negatively related to the pest occurrence, indicating that high temperature and humidity are limiting for this pest in the study region. Provided the periods of highest DBM occurrence, scouting and control measures should be reinforced from June to December. The within-plant distribution of DBM varied both among hosts and between phenological phases (pre- and post-cupping). Our study provides new insights about the timing of DBM peaks, and how the climatic variables affect its dynamics on brassica crops. This information contributes to a better DBM management in Southeast Brazil.

中文翻译：

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气候和寄主植物调节小菜蛾（Plutella xylostella）的季节性动态和植物内分布

摘要 小菜蛾Plutella xylostella L. (Lepidoptera: Plutellidae) 是世界范围内对芸苔属植物危害最大的害虫。由于据报道 DBM 菌株对大多数杀虫剂具有抗性，因此对这种害虫的文化控制很重要，应根据与该害虫相关的基本信息进行设计。本研究调查了寄主植物和气候对 DBM 季节性动态的影响以及 DBM 在巴西东南部栽培最多的油菜作物（西兰花、卷心菜和花椰菜）中的植物内分布。西兰花和花椰菜分别呈现最高和最低的 DBM 丰度。温度和相对湿度与害虫发生呈负相关，表明高温和湿度限制了该害虫在研究区域。如果是 DBM 发生率最高的时期，则应在 6 月至 12 月加强侦察和控制措施。DBM 的植物内分布在宿主之间和物候阶段（杯测前和杯测后）之间有所不同。我们的研究提供了关于 DBM 峰值时间的新见解，以及气候变量如何影响其对芸苔属作物的动态。这些信息有助于巴西东南部更好的 DBM 管理。