Photographer: Jon Richfield Source: Wikimedia Commons Copyright: CC BY-SA 3.0
The hemp broomrape (Orobranche ramosa) also called the branched broomrape is an annual or perennial parasitic plant. The seedlings grow below the ground forming a yellow juvenile plant that is shaped like a spike. Once maturity is reached the plant is 4-12 inches tall with pale to bright yellow coloring. The stems are slender and covered with short hairs. This plant often has many branches arising from the base with leaves similar to scales that alternate along the stem. This plant blooms in October and November with blue/violet flowers similar to a snap dragon.
Habitat: Ornamental and vegetable crop fields, especially tomato fields.
Hemp broomrape is a worldwide noxious parasite of many crops and associated weeds. Heavy infestations can severely damage crops. The hemp broomrape can often be found parasitizing ornamental and vegetable crop fields, especially tomato fields.
The hemp broomrape reproduces by seed, which can be dispersed by human activities, farm macinery, water, and wind. It is common for seeds to be found in contaminated soil that was not properly inspected. The seeds are yellow-brown in color and angular, or egg shaped.
Orobanche ramosa is native to the Mediterranean area of southern Europe but has been spread to a number of other parts of the world.
CA, IL, KY, NC, NJ, TX
There are several native broomrapes in California, a few of which are uncommon to rare, but only Cooper's broomrape occurs in the Mojave and Sonoran deserts (excluding desert mountains) and is a weed of vegetable crops.
Hand pulling plants, plowing under trap crops before seed production, or burying seed with one deep inversion plowing can help control infestations of hemp broomrape.
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Dhanapal, G. N., P. C. Struik, M. Udayakumar, and J. M. Timmermans. 1996. Management of Broomrape (Orobanche spp.) - A review. Journal of Agronomy and Crop Science 175:335-359.
Foy, C. L., R. Jain, and R. Jacobsohn. 1989. Recent approaches for chemical control of broomrape (Orobanche spp.). Reviews in Weed Science 4:123-152.
Holm, L., J. Doll, E. Holm, J. Pancho, and J. Herberger. 1997. Obligate parasitic weeds: Orobanche ramosa L., and Orobanche minor Sm. In 'World Weeds: Natural Histories and Distribution' pp. 511-530 (John Wiley & Sons Inc: New York).
Mitich, L. W. 1993. Orobanche-The Broomrapes. Weed Technology 7:532-535.
Musselman, L. J. 1980. The biology of Striga, Orobanche, and other root-parasitic weeds. Annual Reviews of Phytopathology 18:463-489.
Stout, G. L. 1938. A recurrence of broomrape (Orobanche ramosa L.) on tomato plants in California. California Department of Agriculture Bulletin 27(2):166-171.