Faba bean is a poor competitor to weeds, particularly in the seedling stage or under moisture stress. Appropriate control of perennial weeds during the years preceding faba bean, and use of clean seed, are important for successful production.
To prevent the spread of fungal diseases, post-emergent harrowing should be avoided during:
- crop emergence;
- during damp weather; or
conditions of heavy dew.
Harrowing can occur after the crop seedlings are five to 15 cm (two to six in.) high. An increased seeding rate should be considered to compensate for the loss of crop seedlings during harrowing. Tine harrows are the most effective across the direction of seeding with a ground speed of six kph (four mph) or less. Best weed control will be obtained by harrowing on a dry, sunny day.
A pre-emergent burnoff application of glyphosate will help control winter annual and early emerging weeds. Products containing phenoxy herbicides such as dicamba or 2, 4-D should not be used before or just after planting. Express SG may be applied as a tank mix with glyphosate 24 hours before seeding faba bean.
The following herbicides are registered for use on faba bean: ASSURE II (quizalofop). BASAGRAN, BASAGRAN FORTE, EDGE, SENCOR, POAST ULTRA, and Trifluralin products. For more information on registered herbicides consult the Guide to Crop Protection or the product labels.
Pre-Harvest Weed Control
The use of pre-harvest applications of glyphosate is registered on faba bean and may be used to control perennial weeds, in the following crop, such as:
- Canada thistle
- Common milkweed
Faba bean is subject to a number of diseases that can reduce yield and quality. Infection can come from a variety of sources. Seed borne, soil borne and residue borne diseases can be minimized through preventative management.
Disease prevention recommendations include:
- Use of effective crop rotations;
- Plant faba beans only once in four years in the same field (Continuous production of broadleaf crops can increase some seedling diseases and Sclerotinia stem rot);
- Use of the best seed available;
- A seed test will indicate the presence of seed-borne diseases;
- Early seeding; and
- Monitoring of fields for diseases.
Seed rot, seedling blight, and root rot of faba bean are caused by Fusarium spp., Rhizoctonia solani, Pythium spp., and Aphanomyces euteiches. To reduce the incidence of this complex of seedling diseases, follow a crop rotation that does not include faba bean or other legumes more than once in four years and plant in well-drained soils. Faba bean shows a strong degree of resistance to Aphanomyces euteiches.
There is no seed treatment fungicide registered for use on faba bean.
Chocolate spot of faba bean is caused by Botrytis fabae and Botrytis cinerea and can be residue-borne or seed-borne. Follow a crop rotation of four years between successive crops of faba bean and avoid buckwheat in the rotation. Use seed from disease-free fields. Current research is looking at the epidemiology of chocolate spot.
Ascochyta leaf and pod spot is caused by Ascochyta fabae. It is a seed and residue-borne disease which causes stem, leaf and pod spotting. In severe infections, seeds developing in the pods become discoloured and shrivelled. Follow a crop rotation of four years between successive crops of faba bean to reduce the risk of this disease and use disease-free seed. See the Guide to Crop Protection for registered products for the control of ascochyta blight on faba bean.
Sclerotinia stem rot, which is common in sunflower, canola, dry bean and pea, may become a problem in faba bean. Faba bean should follow a cereal crop in the rotation, rather than an oilseed or legume crop. LANCE® and Acapela (suppression only of white mould) are registered for the control of sclerotinia on faba bean.
Anthracnose is caused by Colletotrichum truncatum. Avoid growing faba bean after lentils in areas where the disease is present. Follow a crop rotation of four years.
Bean yellow mosaic virus (BYMV) can be found on faba bean. Other legume crops are susceptible to this virus; therefore, avoid planting faba bean in close proximity to established fields of forage legumes.
Rust is caused by Uromyces fabae. A crop rotation of at least two years between faba bean crops should be used to reduce build up of the disease. HEADLINE EC fungicide is registered for the control of rust on faba bean. Application should be made at the beginning of flowering or the onset of disease symptoms. Apply a second application 10-14 days later if the disease persists or weather conditions are favourable for disease development. The pre-harvest interval is 30 days with no more than two applications per season.
Other plant diseases of minor importance that have been reported on faba bean are:
- Alternaria leaf spot (Alternaria alternata);
- Aster yellows; and
- Powdery mildew (Microsphaera penicillata var. ludens).
HEADLINE EC is registered for the control of powdery mildew on faba bean. Over use of specific fungicides may lead to development of resistant patholgens.
For more information on plant diseases of pulse crops consult Diseases of Field Crops in Canada available from the University Extension Press, University of Saskatchewan, telephone (306) 966-5565.
For more information on fungicides, consult the publication Guide to Crop Protection or the product labels.
Grasshoppers can be a major insect pest of faba bean. Grasshoppers will selectively consume faba bean plants in areas where other crops are present.
Lygus bugs can cause quality loss in faba bean, as they will move into the crop after other crops have matured and feed by using their sucking mouth parts to make pin holes in the seed coat.
Three species of caragana or blister beetle (Figure 6) will attack faba bean. Blister beetles often attack faba beans in swarms but generally in small patches within the field. They usually do not continue feeding for very long before moving elsewhere. Control measures are difficult to employ, and there are no established action thresholds for faba bean.
Other insects reported on faba bean are leafhoppers and aphids<.
The Saskatchewan Agriculture publication, Guide to Crop Protection contains more information about insecticides registered for use on field crops. Currently, the only insecticide registered for use on faba bean is Matador.
Faba bean seedlings are tolerant to late spring frosts allowing the crop to be planted early. As pulses often mature from the bottom of the plant toward the top, early fall frost injury may be much greater on plant tops. Seeds developing closer to the ground may have little frost damage and care should be taken to focus harvest efforts on these seeds.
During early pod fill, a frost can cause discoloration and deformation of seeds.
Pulse crops should be monitored after a frost to determine the level of injury to the pods and seeds. If the majority of the seeds are not damaged, harvest should continue as planned. If the great majority of pods and seeds are damaged, consider harvesting the crop for feed, but keep in mind the risk of nitrates.
- Frost damaged pods and seeds will be water soaked and no longer firm as they start to "leak".
- Heavily damaged pods will have a rubbery wilted appearance.
There are some products registered for use as a harvest aids on faba bean. See Weed Control Table in the current Guide to Crop Protection.
Next: Faba Bean Harvesting