Wild Mustard (Sinapsis arvensis, a.k.a. Brassica kaber)

Wild Mustard (Sinapsis arvensis, a.k.a. Brassica kaber) Information

By Ronnie Dauber, Garden Guides Contributor Wild Mustard is an aggressive annual weed that is ingenious to Europe, Asia and North Africa, and has now become common in the northern part of North America, namely Canada. It is found in cultivated fields, gardens, pastures, river banks, roadsides and waste places in Ontario, creating a serious problem in potential yield and seed quality of harvested crops. Wild Mustard weeds are responsible for a large percentage of crop losses because it overpowers the crops and destroys them. It can also become fatal to cattle when it is mixed in with the pasture greens and digested in large quantities. As well, it is a popular host to many pests, insects, fungi and viruses that cause severe damage to cultivated crops.

General Characteristics

Wild Mustard ranges in height from 30 to 100cm, and can have either single or multi-branched stems which are greenish/purple. Bright yellow flowers about 1.5cm wide grow in clusters at the end of each branch, elongating as the seedpods develop. Each plant produces about 10 to 18 seeds per pod, and about 2,000 to 3,500 seeds per plant. The seeds are distributed when the intended crops are harvested and the seeds are strewn into the ground and spread to other fields by harvesting machinery. The seeds can remain viable in the soil for up to 60 years because they are buried deep when the ground is cultivated and can come forward and germinate any time.

Growing Conditions

Wild Mustard grows well in almost any soil and prefers full sunlight, although, it can grow well in partial shade.

Cultivation and Care

Wild Mustard is spread when regular crops are cultivated since its crop of Wild Mustard seeds is harvested in the fall when the regular crops are harvested. The care and maintenance given to the regular crops like wheat or barley, encourage this plant to grow well.

Weed Control Techniques

The most successful technique in controlling Wild Mustard is to use regular applications of herbicides. However, Wild Mustard plants are now adapting to many of these herbicides and have become resistant to them. As well, since the seeds can germinate over a long period of time, it is not plausible to allow one field grow only Wild Mustard so that chemicals can be sprayed on to eliminate it, since this process will only remove those plants from those seeds, leaving many more years of supply still in the ground. There are many kinds of chemicals that can be used to get rid of Wild Mustard, and many doses and applications depending on the degree of the infestation. It is suggested that people wanting the proper technique should contact the Ontario Ministry of Agriculture and Food Publication 75, Guide to Weed Control.

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