Coopers 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
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.
back to top
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.
with very short, glandular hairs. Leaves reduced to alternate
and UNDERGROUND STRUCTURES:Roots modified to attach directly to host plant
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.
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.
by seed. Seed disperses with human
activities, farm machinery, water, and wind.
back to top
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.
are several native broomrapes in California, a few of which are uncommon to
rare, but only Coopers 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.
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.
back to top of page