336 



Dodder. 



[SEPT., 



4. Where dodder is found infesting a crop, however small the 

 patch, steps should at once be taken to destroy it. This may 

 best be done by digging up the infested plants and burning the 

 whole, /;/ situ, by covering the area 6-9 inches thick with long 

 chaff, sprinkling it with paraffin, and then firing it. It is wise 

 not to remove the infested plants for burning, as small pieces left 

 on the field or dropped in fresh places may only serve to spread 

 the infection. It is better to lose completely a small area of the 

 crop by burning than to take risks and possibly have a much 

 more serious infestation another year, especially since dodder 

 seed may lie dormant in the soil for five or six years. 



5. An infe-sted field should not be allowed for a few years to 

 carry a clover, lucerne or other leguminous crop. 



6. Thaer recommends that the infested spot be surrounded 

 by a small trench at a suitable distance from the outermost 

 threads of dodder, the soil removed from the trench being 

 thrown on the infested spot. This method, or burning with straw, 

 he considers to be better than the employment of corrosive 

 'substances, sulphate of iron, large quantities of super- phosphate, 

 or the refuse liquor from the manufacture of sulphate of ammonia, 

 all of which work certain destruction to dodder. Such sub- 

 stances, however, ruin the soil for one or more years after use. 



7. Tearing out the dodder with a rake is to be condemned, as 

 this only serves to spread the evil. 



8. Infested clover or lucerne should not be fed to stock, 

 as the seeds may pass through the alimentary canal unaffected, 

 and Frank mentions a case in which a field was actually infected 

 by means of manure from young cattle, which had been fed on 

 rape and linseed cake containing dodder seed whose germinating 

 capacity had not been destroyed. 



9. Frank suggests that substances which will smother the 

 dodder may be effectually employed, such as a layer three 

 inches deep of chaff, tan or gypsum, covered with an inch or so 

 of fine soil and saturated with liquid manure or sprinkled with 

 powdered quicklime in winter. The clover wall generally break 

 through such coverings but the dodder will be unable to do so. 



10. In cases where the infestation is very extensive, covering 

 the larger part of the crop, it is perhaps better to plough the 

 whole under before seeds are formed. 



