Climate and host plants mediating seasonal dynamics and within-plant distribution of the diamondback moth (Plutella xylostella)

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.