Winter weeds and its control in the medicinal plants in Egypt: a survey study

Abstract

Weed control is the main obstacle in the production of medicinal plants, especially in organic farming where the growers cannot use synthetic herbicides. For understanding the impact of weeds on the productivity of medicinal plants, the common weeds and weed control practices of more than 20 cultivated medicinal plants were evaluated in eight regions in Egypt with several of climatic conditions and soil types. All tested farms that have applied the organic farming systems and their products are mainly for export. The large-scale weed surveys have shown that the most problematic weed species in medicinal plant crops is Senecio desfontainei because it is content of pyrrolizidine alkaloid plants. The dominant weeds associated with the medicinal plant fields were Malva parviflora (16.8%), Chenopodium album (12.4%), Medicago intertexta (8.8%), Anagallis arvensis (8.8%), Sonchus oleraceus (6.2%), Beta vulgaris (5.3%) Brassica kaber (5.3%), Cichorium pumilum (3.5%), Melilotus indica (3.5%), Euphorbia geniculata (3.5%), S. desfontainei (1.8%), Emex spinosus (0.9), Solanium nigrum (0.9%), and Conyza linifolia (0.9%). The narrow-leaf weeds are Lolium multiflorum (7.1%), Avena fatua (6.2%), Phalaris minor (2.7%), and Polypogon monspeliensis (1.0%). The perennial broad-leaf and narrow-leaf weeds were Convolvulus arvensis (3.5%) and Cyperus rotundus (0.9%). The results of the survey indicated that the crop type and location had a significant effect on weed species and their frequencies and abundances. The common practice for weed control in the medicinal plants is hand weeding, mulch, acetic acid, presowing false irrigation, and mechanical weeding (in limited area). The efforts must be taken regarding search for safe, new, and nontraditional weed control methods to apply in the medicinal plant fields.