Weeds: A Major Threat to Medicinal Plant Yield and Quality

Subject Areas : Medicinal Plants

M Minbashi Moeini ¹ , N. Nizamabadi ² , M. Younes Abadi ³ , Abdulaziz Haghighi ⁴ , L Habibian ⁵ , T Soleimani ⁶ , Ali reza Safahani ^{7 *}

1 -
2 - موسسه تحقیقات گیاه پزشکی
3 - Plant Protection Research Department, Golestan Agricultural and Natural Resources Research Center, AREEO, Gorgan, Iran.
4 - Plant Protection Research Department, Golestan Agricultural and Natural Resources Research Center, AREEO, Gorgan, Iran,
5 - Plant Protection Research Department, Golestan Agricultural and Natural Resources Research Center, AREEO, Gorgan, Iran.
6 - Graduate in Plant Pathology, University of Zabol
7 -

Received: 2025-01-19 Accepted : 2025-03-05 Published : 2025-03-21

Keywords: Competition, Yields, Essential oil, weeding management, Critical period for weed control, Relative losses.,

Abstract :

Competition with weeds has significant negative effects on the yield and quality of medicinal plants. The extent of these effects depends on the type of medicinal plant, the harvested part, environmental conditions, and the level of weed infestation. Unlike other crops, medicinal plants are cultivated to produce specific secondary metabolites that determine their quality and medicinal value. Weed growth can reduce the active compounds in medicinal plants and alter their metabolic pathways, leading to unpredictable fluctuations in the chemical composition of the final product. The intensity of weed competition varies depending on the timing and duration of weed presence. Early weed infestation is usually more damaging since weeds grow faster than medicinal plants. In some cases, crops must remain entirely weed-free for up to 60% of their life cycle to minimize damage. Various methods are used to control weeds, each having different effects on medicinal plant production. The use of herbicides has shown contradictory results and, in some cases, has interfered with the production of secondary metabolites. In contrast, non-chemical methods such as manual weeding, mechanical treatments, mulching, burning, and even grazing by sheep and goats have been studied. With the growing interest in organic farming, further research is needed on the impact of weeds on metabolic pathways and strategies for weed management in different cultivation environments.

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