Filters

Weeds - Faba Bean

Contributors to this section: ICARDA, Syria (Siham Asaad, Abdulrahman Moukahal).

Contents:
Broomrape, Branched Broomrape
Dodder

Broomrape, Branched Broomrape

Scientific names

Orobanche foetida Pers.
Orobanche crenata Forsk.
Orobanche ramosa L.

Significance

Yield reductions of 30 to 70% are not uncommon. International markets may reject broomrape-contaminated produce.

Symptoms

The appearance of the parasite itself is the most diagnostic feature of infestation. The parasite has erect, branched or unbranched aerial flowering shoots. The leaves are reduced to scales and are disposed alternatively. The shoots bear bisexual tubular flowers in a spike. The tiny seeds are produced in enormous numbers in capsules.

Hosts

Broomrapes usually parasitic only broadleaved plants but there are a few records of attacks on monocots (grasses, etc.). Branched broomrape attacks many crops and common weeds. Non-host crops can support infestations because of their weed component, and the produce of such crops may carry broomrape seeds. Some broomrape species have specialized biotypes or races. Plants of the same species attack different sets of hosts in different geographic areas. Susceptibility to attack also depends on the cultivar or genetic characteristics of a particular crop. The plants attacked by branched broomrape around the world include:

Crops: bean, broad bean, cabbage, capsicum (peppers), canola, carrot, cauliflower, celery, chickpea, clovers, eggplant (aubergine), flax, hemp (cannabis), hops, lentil, medics, onion, parsnip, paprika, pea, pyrethrum, sunflower, tobacco, tomato, potato.

Geographic distribution

Western and Central Asia (especially in Afghanistan, Syria, Egypt, India, Iran, Jordan, Lebanon, Morocco, Pakistan, Saudi Arabia, Australia, Europe (especially the Mediterranean), N. Africa, N. America.

Biology and transmission

Seeds germinate in moist soil at 18 to 23° C and require moist soil for one week to become established. The roots parasitic the roots of host plants for 40 to 50 days. Stems emerge in spring and are visible for only about 3 weeks from the end of September through to October. Flowering is rapid, within 6 to 9 days after stem emergence, with a similar period between the cessation of flowering and the ripening of fruit. An infestation may contain many plants that do not produce above-ground parts.

Dispersal from property to property and within properties in the infested area in South Australia appears to be mainly by carriage on vehicles and machinery. Seeds stick to equipment and animals that contact the plant and can also be dispersed by wind and water (including irrigation water/sprinklers), in animal manure, soil, fodder, on livestock and on footwear and clothing. Seeds attach to crop seeds and other produce. Seedlings imported from infested areas can carry seeds stuck to their leaves or in the soil. Seeds remain viable after passage through the digestive tracts of animals including cattle and goats.

Detection/indexing method in place at the CGIAR Center at ICARDA

Treatment/control

Hand weed shoots prior to their seed formation to reduce inoculum levels. This is recommended in minor infestations only.

Procedure followed at the centers in case of positive test

References and further reading

http://www.icarda.org/Publications/Field_Guides/Lentil/Lentil.htm#Lent7.Html

Branched Boomrape – Identification: State prohibited weed

Orobanche foetida (photo: ICARDA)

Orobanche crenata (photo: ICARDA)

Orobanche ramosa (photo: ICARDA)

Orobanche egyptiaca (photo: ICARDA)

Back to top


Dodder

Scientific names

Cuscuta campestris Yuncker
Cuscuta hyalina Roth.

Other scientific name

C. pentagona

Significance

The effect of field dodder on 12 legume crops was investigated in a greenhouse experiment. The legume crops showed great variations in response to field dodder parasitism. Based on the reduction in host dry weight (biological yield) caused by the parasite, faba bean lost >50% of its biological yield was considered highly susceptible.

Symptoms

The appearance of the parasite itself is the best diagnostic symptom. It has fine, yellow or orange, thread-like branches which grow and entwine around the stems and other aboveground parts of the host.

Dodder-infected areas appear as patches in the field and continue to enlarge during the growing season. In late spring and early summer, dodder produces a massed cluster of white flowers.

Infected host plants become weakened, decline in vigor and produce poor yields.

Several patches might coalesce to form large areas that can be easily recognized by the yellowish color of the parasite strands.

Hosts

C. campestrisis the most important Cuscuta species, attacking a wide (C. campestris) range of species, including vegetables, fruits, ornamentals and woody plants. It is reported as a weed in 25 crops in 55 countries.

Geographic distribution

Europe to North Africa and eastern Asia

Detection/indexing method at ICARDA

Treatment/control

Procedure followed in case of positive test

References and further reading

 http://www.icarda.org/Publications/Field_Guides/Lentil/Lentil.htm#Lent7.Html

http://www.weedalert.com/weed_pages/wa_dodder.htm

Dodder (photos:ICARDA)

Back to top

The Genebanks

The 11 CGIAR genebanks currently conserve 730,000 of cereals and grain legumes, forage crops, tree species, root and tuber crops, bananas and crop wild relatives.

close-icon