The most common weeds in barley farming belong to the families Asteraceae, Poaceae, and Brassicaceae. They are the following (Mennan and Pala, 2018), (1):
- Wild oat (Avena fatua)
- Charlock mustard (Sinapis arvensis)
- Sticky willy (Galium aparine)
- Greater bur parsley (Turgenia latifolia)
- Flanders poppy (Papaver rhoeas)
- Field chamomile (Anthemis arvensis)
- Creeping thistle (Cirsium arvense)
- Asiatic witchweed (Striga Asiatica)
Some general principles in the use of herbicides are (2):
- Always discuss with your local licensed agronomist before applying any herbicide. Irresponsible use of herbicides will have dramatic effects.
- Follow the dose and time recommendations on the product’s label.
- After the application, check the field regularly to ensure the problem has been controlled successfully. Keep in mind that weeds can reproduce by seed or proliferate vegetatively.
- Cleaning the equipment is crucial if a farmer wants to minimize weed seed spread between fields.
- Starting with a clean field and controlling weeds very early is always recommended. Some growers use a burndown treatment, while others apply tillage combined with a pre-emergence residual herbicide.
- Use agronomic practices that improve crop competitiveness for resources against weeds.
Another measure that could help in weed control is the narrow row spacing since, in this way, there is not enough space for weeds to emerge. A common herbicide used in barley farming is the MCPA, and it’s applied early in the spring. MCPA has been used to a great extent to control broad-leaf weeds since 1945. MCPA acts as auxin, a growth hormone that naturally exists in plants, and its salt or esterified forms are used as herbicides (Grossmann, 2010). For winter wheat, it has been reported that metribuzin plus metolachlor, metribuzin plus oryzalin, and metribuzin plus pendimethalin controlled broad-leaf weeds successfully (tillage systems) (Diawarra et al., 1990).
Like integrated pest management, “Integrated weed management is the coordinated use of a variety of control methods, reducing reliance on herbicides alone, and increasing the chances of successful control or eradication. Integrated weed management programs require long-term planning, knowledge of a weed’s biology and ecology, and appropriate weed control methods” (2).
Biological control of weeds refers to using a plant’s natural enemies such as insects, mites, and diseases to reduce and/or control the weed population. It is an economically effective and environmentally friendly method, but it requires time for the development and establishment phases to be completed. Biocontrol will not eliminate weeds, but it can reduce their population to an acceptable level or/and facilitate their control with other methods (2).
Weeds’ existence in barley can cause yield reductions and degradation of the quality of the harvested product. Weed management before, during, and after crop emergence is essential. Weed management in barley depends, until today, mainly on herbicides for weed control, and this approach has resulted in widespread herbicide resistance worldwide. A fundamental problem in weed management is weed resistance. A solution could be crop rotation, which means planting break crops such as potatoes, rape and beans between cereals cultivations. The different sowing dates, growth habits, and herbicides can decrease the possibility of weeds developing resistance (3). There are some specific groups of herbicides for which no weed resistance has been reported until today.
In every case, you should consult a licensed agronomist before adopting any weed management measures.
- Grossmann, K. (2010). “Auxin herbicides: current status of mechanism and mode of action”. Pest Management Science. 66 (2): 2033–2043.
- Mennan, H., Pala, F. (2018). Major weeds in Barley Fields of Diyarbakir, Belgium
- Diawara, M., Banks, P. (1990). Weed Control in Barley (Hordeum Vulgare) – No – Till Grain Sorghum (Sorghum bicolor) Production
Weed Management in Barley Farming