Research concerning control of the large cabbage white (Pieris brassicae) larva in the oilseed rape crop from south-east Romania

Abstract

Large cabbage white (Pieris brassicae) was considered a secondary pest of the oilseed rape (OSR) crop during the autumn period in Romania and a primary pest of the cabbage crop. This study monitored the attack of the P. brassicae larva on both OSR untreated and treated seeds with cyantraniliprole active ingredient (625 g/l) at the experimental field from NARDI Fundulea, located in the southeast of Romania between 2019 and 2021. In the autumn of 2019, on 28 October, at OSR untreated plants, the attack degree was 12.49 %, while at the seed-treated variant, the attack degree was 4.30 %. On 6 November, the attack degree was 38.58 % in the untreated variant, while in the treated variant, it was 8.77 %. In the autumn of 2020, it registered higher attacks from this study. On 11 November, the attack degree was 53.07% in the untreated variant, while in the treated variant with cyantraniliprole a.i. the attack degree was 22.14%. In 2021, it didn’t register the attack of this pest in the experimental field. A possible explanation is the delayed emergence of the OSR plants at the end of October. Regarding pest density, this study shows that in the autumn of 2019, on 6 November, the untreated variant registered 4.24 larvae/m2 and 2.32 larvae/m2 in the treated variant. In the autumn of 2020, on 2 October, the untreated variant registered 4.82 larvae/m2 and 2.57 larvae/m2 in the treated OSR variant. On 11 November, the pest density was higher than the economic damage threshold at both variants. This study reveals a higher attack of the large cabbage white at OSR crop in southeast Romania, compared with results from the previous studies. At the same time, it registered higher pest’ attacks in November.