Wagon Wheels West
Charlock (Sinapis arvensis) and Wild radish (or Runch) (Raphanus raphanistrum) are a real nuisance in Winter Oil seed rape and of course beans.
Once the seed is in the soil it persists. Charlock seeds buried in uncultivated soil can remain viable for 60 years and can germinate when brought back to the surface by ploughing. Allowing charlock to seed every 11 years is sufficient to maintain the soil seedbank population.
Both have protracted germination patterns, autumn through to spring. Autumn emerging charlock plants may be killed by low winter temperatures but wild radish tends to be more frost-tolerant. The protracted period of germination combined with high seed persistence in the soil makes eradication from fields almost impossible. Establishing spring crops by direct drilling or with minimal soil disturbance may reduce the numbers of charlock and wild radish emerging in the crop.
Nowadays its fashionable to tell the farming community not to be reliant on herbicides for weed control; integrate their use with non-chemical methods wherever possible. With this weed, like many others, I’m not totally convinced about the practicality of that.
Over one hundred years ago, these two species were the most troublesome weeds of arable crops (Common weeds of farm and garden, H C Long, 1910). In the UK, as early as 1897, the value of the first widely used selective herbicide for the control of these weeds was well known, that is some 30 years before MCPA and 2,4-D were discovered.
My father told me that the introduction of herbicides in the 1950’s allowed him to grow a commercial crop of cereals since they were unable to effectively control this highly competitive weed in commercial crops by other methods. Another weed I was well educated in the need for control of was “Wagon Wheels,” but that’s another story.