40 



Corn Cockle. 



[APRIL, 



bitter taste to bread when baked. Their poisonous character 

 is dealt with below (p. 41). 



Corn cockle is a hardy annual, the seed appearing to 

 germinate either in spring or autumn, in the latter case the 

 young plants becoming well established before spring. 

 Thaer says that while botanically an annual it rather appears 

 agriculturally as a biennial, and that the seeds germinate 

 and the first leaves grow at so low a temperature that it 

 appears more as a weed of winter corn than spring corn. 



Harm done. — Corn cockle is an undesirable plant in corn- 

 fields for three reasons : it is a weed in the usual acceptance 

 of the term, aiding to crowd out the cereal crop ; the seeds 

 are poisonous; and the seeds when ground up with wheat 

 discolour the flour, which would be a disadvantage even 

 were the seeds wholesome. 



Prevention and Remedy. — The plant is therefore a weed 

 which should be eradicated. To this end an endeavour 

 should be made to prevent seeding, and this may perhaps 

 be best done, in well-grown corn crops, by hand-pulling the 

 growing plants. Where the weed is known to be very plenti- 

 ful the seeds may be encouraged to germinate by spring and 

 autumn cultivation, the seedlings being subsequently 

 destroyed by harrowing. 



Repeated harrowings of the grain crop may be the means 

 of destroying large numbers of the seedlings. 



It will also be a useful measure to abandon autumn-sown 

 cereals for a time in favour of late-sown spring cereals, in 

 which case the winter and late spring tillage will tend to 

 destroy the young seedlings which have appeared. 



Short rotations will be a great help in getting rid of corn 

 cockle, and thorough cleansing of root crops will kill a 

 great deal of the weed. "It is quickly suppressed and ulti- 

 mately eradicated on lands brought under a short rotation 

 of crops." * 



It may be suggested that, as the seed of corn cockle ripens 

 about harvest time, a box attachment near the horizontal 

 rollers of a self-binder or behind the platform or pan of a 

 reaping machine will catch many seeds which would otherwise 

 be scattered on the stubble. 



* Farm Weeds of Canada. 



