Chemical management of Orobanche in Toria (Brassica campestris L. var. Toria)

Abstract

Orobanche, a parasitic weed, poses a major threat to Toria (Brassica rapa), a vital cash crop for farmers in Assam, particularly in the Nagaon district. Orobanche infestation severely affects crop yield, often leading to crop failure. This study, conducted over three winter seasons (2020–2022) on farmers’ fields in Nagaon, aimed to evaluate glyphosate’s effectiveness in controlling Orobanche and enhancing Toria yield. A treatment protocol was developed based on previous successful applications in mustard, with glyphosate applied at 25 g/ha at 30 days after sowing (DAS) and 50 g/ha between 50–55 DAS. Results demonstrated a significant reduction in Orobanche shoots (up to 90%) and an increase in Toria yield by 50-60%. Prior studies (Punia et al., 2018) supported these findings, indicating that sequential, low-dose applications effectively reduce Orobanche by targeting the EPSP synthase pathway in the parasite. This selective inhibition allows mustard plants to degrade glyphosate into non-toxic metabolites, minimizing crop impact. This research provides a promising, field-tested approach to managing Orobanche in Toria, helping farmers enhance crop productivity and protect against this challenging weed.