Weeds
Orobanche ramosa L. - Branched Broomrape
Systematic position.
Family Orobanchaceae Vent., genus Orobanche L.Biological group.
Annual parasite.Morphology and biology.
Stem branchy, shortly haired, with small sparse ovate scales, thickened at base, 40 cm in height. Flowers aggregated in loose oblong inflorescences. Flower bell is saucer-shaped, four-toothed. Fruit is bivalve box, 6-7 mm in length. Seeds fine, elliptic or rounded, easily spread by wind, - about 0.4 mm in length, 0.2 mm in width. Seed surface reticulate, grayish-brown. Fruitfulness of one plant is to 100,000 seeds. Viability keeps 5-7 years. Weight of 1,000 seeds is 0.02 g. Shoots of the Branched Broomrape appear on ground surface after fixation on roots of host-plant. Germinated seeds give albesent threadlike processes sticking to roots of affected plants with suckers. Blossoms in June - August, fructifying in July - September.Distribution.
The species is distributed in southern areas of the European part, in the Caucasus, and Crimea.Ecology.
The parasite sticks to shoots of weeds, wild-growing and cultural plants.Economic significance.
The species parasitizes mainly on such annual wild-growing and cultural plants as tobacco, tomato, melon, pumpkin, carrot, fennel, coriander, sunflower, mustard, cabbage, horseradish, sweet clover, peanut, haricot, hemp, hop. It is especially dangerous to hemp, tobacco, tomato. It parasitizes also on weeds, e.g., nettle, wormwood, melilot, false flax, etc. The affected plants grow poorly, reduce yield, sometimes perish. Control measures include seed cleaning and crop rotation with return of susceptible cultures in 5-8 years to a field infested with Broomrape seeds. Biological method is based on the use of natural fly enemy (Phytomyza orobanchiae) populating the Branched Broomrape at all stages of its development.Reference citations:
Anonym. 2001-2007. Branched Broomrape - Orobanche ramosa L. (in Russian). http://www.agroru.com .Nikitin V.V. 1983. Weeds in the flora of the USSR. Leningrad: Nauka. 454 p. (in Russian).