The snack appears if you search “tiger nuts” on Amazon (Figure 1). It’s organic, non-GMO, nutritious, and fit for keto and gluten-free diets. This snack is consumed in South America, Africa, and some parts of Asia. It can also be further processed into gluten-free flour, ice-cream milk-type extract, and vegetable oils. However, the nutlets look just the same as the ones from the weed commonly known as yellow nutsedge (Cyperus esculentus L.).
Yellow nutsedge is a perennial weed species that belongs to the sedge (Cyperaceae) family. It has narrow, grass-like leaves with yellowish-green color. The stem of yellow nutsedge distinguishes it from grasses, as it is upright, triangular, and has three vertical rows. Yellow nutsedge primarily reproduces through underground rhizomes (Figure 2) and tubers (also known as “nutlets”). One tuber can lead up to 1,900 new plants and over 7,000 new tubers in a single growing season.
Washington state (WA) is one of the top potato-producing states in the US. Most of the potato production in WA comes from the Columbia Basin region. Yellow nutsedge is currently this region’s most problematic weed species for potato growers. It competes with potatoes for nutrients and can grow into potato tubers (Figure 3), decreasing the quality of potatoes. The management of yellow nutsedge is critical to the potato industry.
Integrated weed management (IWM) includes preventative, cultural, mechanical, and chemical methods to control weeds, which we are exploring for yellow nutsedge control. Preventing yellow nutsedge from spreading to new areas can be achieved through cleaning equipment before moving it to a new field, using uncontaminated seed sources, etc. Cultural practices like crop rotation using competitive cover crops could reduce yellow nutsedge population density. Mechanical methods such as tillage or mowing can be used during certain times of the growing season. Chemical control includes using effective herbicide programs that include pre-emergence (PRE) and post-emergence (POST) herbicides, combining herbicides with different modes of action, etc.