Broomrape

Scientific name: Orobanche minor
  • Key characteristics
  • Biology
  • Impacts
  • Control
  • Further information

  • Parasitic plant lacking in green colouration
  • 1-2 cm long, sparsely spaced, scale-like leaves are the same colour as the stem. They can be hairless or have glandular hairs
  • Fleshy-stemmed flower stalks, 10-40 cm tall and about 1 cm across, are the only visible part of plant
  • Flower stalks are light tan to brown and sometimes purple coloured
  • Unscented tubular flowers, 10-15 mm across, yellowish, with many bluish-mauve veins, appear on upper part of flower stalk between August and January
  • Orange-brown root tubers attach to roots of legumes, dandelions and some other plants including shrubs.

Other similar species present in New Zealand

  • Tarweed (Parentucellia viscosa) and red tarweed (Parentucellia latifolia) are similar parasitic weeds, but both have sticky green leaves
  • Tarweed has yellow flowers and the other red flowers. Tarweed is common on roadsides while red tarweed is rare and only found in pastures in a few parts of the North Island.

Origin

  • Native to western Europe and higher altitudes in Africa
  • Broomrape was first found in New Zealand in 1867, near Whangarei, and is now a common weed of crops and pastures and waste places throughout the country.

Life cycle

  • Produces seeds that are about 1/3 of a mm long and readily spread by wind
  • The tiny seeds are stimulated to germinate by secretions from the roots of host plants
  • The emerging root of the broomrape seed attaches itself to a root of the host plant and derives all its nutrition from those plants; lacking chlorophyll, they cannot make food for themselves
  • The plants are perennial, sending up a new flowering shoot each spring and summer for a number of years or until the host plant dies
  • Plants occur on roadsides, disturbed ground, in open pastures and in crops on heavy soils.

Benefits

  • None that we know of.

 Impact on pasture

  • Probably limited effects, although presumably host plants such as clovers are weakened by this parasitic plant
  • Other species of broomrape (especially Orobanche ramosa and Orobanche aegyptiaca) found overseas are considered serious weeds in some crops but these are not found in New Zealand
  • Seeds of these other species are considered serious contaminants of crop seeds in international trade.

Impact on stock

  • No direct effects.

  • In New Zealand, control of this species is not usually necessary, although it has caused yield losses in New Zealand tobacco crops
  • Mowing will reduce seed set or remove unsightly flower heads on lawns and grass berms
  • For other broomrape species found overseas, no single, cheap method of control is effective, so integrated control methods must be used for these more serious species.

Grazing management

  • Usually ignored by livestock.

Chemical control

  • Diquat provides effective control in wasteland areas or prior to cultivation or crop establishment.

Biocontrol

  • The broomrape-fly Phytomyza orobanchia was widely used for Orobanche control in the Soviet Union and some East European countries in the 1960s and 1970s, but Orobanche is not important enough here to warrant its introduction.

Integrated control

  • Trap crops and catch crops are used for control of Orobanche species overseas
  • These crops stimulate germination of Orobanche in the soil to deplete the seed reserves
  • Trap crops promote Orobanche seed germination but do not support parasitism
  • Catchcrops support parasitism but are destroyed prior to Orobanche flowering.

  • CABI 2014. Orobanche minor. Invasive Species Compendium. (accessed 14 October 2014) Read full text
  • Habimana S, Nduwumuremyi A, Chinama JD 2014. Management of Orobanche in field crops – A review. Journal of Soil Science and Plant Nutrition 14: 43-62. (accessed 13 October 2014) Read full text
  • James RW, Frater KC 1977. The control of broomrape (Orobanche minor) in flue-cured tobacco. New Zealand Tobacco Growers Journal October: 10-13.
  • Popay I, Champion P, James TK 2010. An illustrated guide to common weeds of New Zealand. New Zealand Plant Protection Society, Christchurch, New Zealand. 416 p.