NETTLE

Nettles are hardy perennials that form large clumps up to 1.2m (4ft) in height. Unlike deadnettles (Lamium), stinging nettles (Urtica) have stinging hairs that make them quickly apparent to the gardener when weeding. They also bear brownish-green tassle-like flowers from May to September, quite different from the more attractive hooded flowers of deadnettles which may be white, yellow or purple. Male and female flowers are on separate plants. In addition to perennial nettles (Urtica dioica) there is also annual nettle (Urtica urens) are usually considered to be weeds.

Crop competition and contamination Some impacts of this weed in row crops include:
• crop nutrition deficiency;
• competition for light and water; and
• crop contamination. Early emergence and rapid growth rate gives dwarf nettle a competitive advantage over crop plants. Contamination can result in significant removal costs during processing, or lower prices at sale. Contamination has been particularly noted as a problem for machine-harvested cut-leaf vegetables such as spinach and baby leaf lettuce.
A host of pests and diseases Dwarf nettle hosts a range of vegetable crop pests and diseases in Australia and elsewhere around the world. These include Pratylenchus nematodes, viruses (including cucumber mosaic virus), Verticillium wilt, and aphids.

Dwarf nettle is a common weed of disturbed sites such as fence lines, earth banks and roadsides, in addition to being problematic in vegetables and other horticultural crops. It is widespread in all Australian states, particularly in the south-east, and is noted as a significant weed of vegetable production.

Spray FireHawk Bioherbicide Concentrate: 50 mL/L of water. Respray when regrowth occurs from roots and/or runners. May require repeated application to obtain long-term weed control.