632 Journal of Agriculture, Victoria. [10 Oct., 1918. 



die on exposure to sun or wind, and each fresh cultivation of the soil 

 brings more seeds within the influence of warmth and air, thus inducing 

 germination, and further cultivation is then necessary to destroy these 

 late growths. On the other hand, if cultivation be not carefully carried 

 out it may spread such plants as Canadian Thistle and St. John's Wort, 

 for small pieces of the roots of such weeds are each capable of forming 

 new plants, and the harrows, in dragging these about, may easily start 

 a fresh patch. 



Seeds deeply buried often remain dormant for very long periods, so 

 that deep plowing sometimes buries many seeds too deeply in the ground 

 for germination to take place immediately, but they will germinate when 

 subsequent plowings bring them to, or near, the surface. 



Cultivation for the suppression of perennial weeds must be frequent 

 enough to stop the formation of leaves, thus preventing the elaboration 

 of crude sap sent up by the roots, and then the plant will be gradually 

 suffocated and will die. Plowing should be of varying depths, so that 

 all the roots may be brought to the surface to enable wind or sun to dry 

 them out. 



One of the chief means of controlling weeds, especially perennials, is 

 to stop the development of seeds. This may be achieved in many ways, 

 such as by mowing the plants, hand-pulling, or by digging them out. 

 Heavy stocking with sheep or goats when the plants are young is often 

 effective. The planting of strong-growing crops to smother weeds has 

 also proved useful. Where it is found impracticable to employ these 

 methods, chemicals can be used effectively to destroy all growth above the 

 ground. Small patches of very persistent weeds can be killed by 

 covering them with heavy mulchings of straw, sheets of bark, sheets of 

 heavy paper, or, in fact, any material that will exclude all light from 

 them, it being impossible for any plant containing chlorophyll in its 

 leaves to exist in total darkness. 



The best time to attack weeds by mowing them is just before they 

 come into full bloom. This is especially so with annuals and biennials, 

 as at this time their roots are more or less exhausted, their reserves 

 having been fully drawn upon to enable them to reach the flowering- 

 period. 



In the case of perennials this exhaustion is not so pronounced; still 

 the check administered by destroying all top growth at this stage, either 

 by mowing or by the application of chemicals, is severe, particularly so 

 when the latter means are adopted. Chemical sprays should be applied 

 during warm weather, care being taken to see that all parts of the plant 

 above ground are touched by the mixture. Special attention must 

 always be given to insure that the collar of the plant receives its full 

 share of the material. 



There is no royal road to weed control, but if land-owners decided 

 on concerted action much could be achieved, for the hope of success lies 

 more in practical work than in thinking over such matters. They should 

 always be alert to prevent weeds spreading from their strongholds into 

 clean country. This can only be effected by vigilance and promptitude 

 in combating fresh patches as soon as they make their appearance. If 

 nothing is done to check them, they will shortly increase to formidable 

 proportions, and the cost of their eradication later on must be propor- 

 tionately increased. 



