Cooper’s broomrape or Desert broomrape[Orobanche cooperi (A. Gray) A.A. Heller][Bayer code: none][CDFA list: A] Photographs Map of Distribution

Branched broomrape [Orobanche ramosa L.][ORARA][CDFA list: A] Photographs



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[
SYNONYMS] [GENERAL DESCRIPTION] [SEEDLINGS] [MATURE PLANT] [ROOTS and UNDERGROUND STRUCTURES] [FLOWERS] [FRUITS and SEEDS] [HABITAT] [DISTRIBUTION] [PROPAGATION/PHENOLOGY] [MANAGEMENT FAVORING/DISCOURAGING SURVIVAL] [SIMILAR SPECIES] [CONTROL METHODS]

SYNONYMS:

GENERAL DESCRIPTION:Annual or perennial non-photosynthetic root parasites that lack chlorophyll and conspicuous foliage. Plants are visible above ground only while flowering and annual or perennial, depending on the life cycle of the host.

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SEEDLINGS:Not visible above ground. Host plant roots can have root nodules that resemble those caused by root-knot nematode or attached bullet-shaped to asparagus-like broomrape plants.

MATURE PLANT:Covered with very short, glandular hairs. Leaves reduced to alternate scales.

ROOTS and UNDERGROUND STRUCTURES:Roots modified to attach directly to host plant roots.

FLOWERS:Two-lipped, sessile or on a short stalk with 2 small bracts, typically with more than 20 flowers per infloresence. Stigmas 2-lobed or shield-like. Stamens 4, included within flower tube.

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FRUITS and SEEDS:Capsule 1-chambered, opens by 2 valves at the apex to release numerous seeds 0.3-0.5 mm long. Seeds angular-ovate, yellowish-brown, with a dull, net-like (reticulate) surface.

HABITAT:

DISTRIBUTION:

PROPAGATION/PHENOLOGY:Reproduces by seed. Seed disperses with human activities, farm machinery, water, and wind.

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MANAGEMENT FAVORING/DISCOURAGING SURVIVAL:Hand pulling plants, plowing under trap crops before seed production, or burying seed with one deep inversion plowing can help control infestations.

SIMILAR SPECIES: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. Unlike branched broomrape, native broomrapes have 5-lobed calyces.

CONTROL METHODS

Prevention and control: Orobanche ramosa is a serious threat to tomato production in California. Plant only certified seed and clean nursery stock to avoid introducing Orobanche species into production fields. Orobanche seeds are very small and easily separated from most crop seed grown in California. However, seed are also easily transported on contaminated equipment and in irrigation or flood water, Additionally, O. ramosa may survive on several hosts other than tomato including many common agricultural weeds. Surveys of infested or previously infested fields should include surrounding field borders that may act as a refuge. Seed may survive in the soil for many years, so repeated annual monitoring is essential. Strategies for dealing with infestations include hand removing plants before flowering, planting trap crops that will induce Orobanche to germinate followed by cultivation before flowering and soil fumigation. Heavily infested fields may need to be rotated to non-susceptible crops for at least two years.

References:
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.

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