198 



The Suppression of Weeds. 



[June, 



not only were various baits and proprietary poisons tested, but 

 many experiments were conducted to elucidate the active agent 

 in red squill and to obtain more certain information as to the 

 minimum lethal dose, and the suitability of various squill 

 poisons. Several series of experiments were also carried out 

 to investigate the action of barium carbonate and other sorts 

 of barium, but the results proved unexpectedly variable, and 

 it is difficult to draw from them any satisfactory generalisation. 

 Experiments were continued on the question of the palatability 

 of various vehicles, especially cereals. 



The number of premises treated by bait from the factory in 

 1921-2 was 776 (compared with 295 in 1920-1). and the number 

 of treatments applied amounted to 1.644 (687 in 1920-1). In 

 many cases the initial treatment resulted in the premises being 

 completely freed from rats and mice, and 326 cases have been 

 recorded in which treatment was very definitely successful. In 

 the other cases the application of the bait proved successful, 

 and further treatment was requested. 



It is regretted that owing to the closing down of the Eat Bait 

 Factory and Research Laboratory the services rendered and the 

 research undertaken will have to cease. 



The part played by weeds in farm economy has long been 



recognised by practical farmers, and the Ministry has repeatedly 



. directed attention to the subject since the 

 The Suppression , nAA . . , fl , J n , . , , 



of Weeds ^ ear ' wnen * ne leaflet on Charlock 

 was first issued. Since that date a widely 

 distributed leaflet (Weeds and their Suppression) has given con- 

 densed information on the damage done by weeds, the manner 

 of their distribution, and the general methods which may be 

 brought into requisition in suppressing them. Other leaflets 

 deal specifically with certain of the more troublesome weeds. 



Weeds of different species vary considerably in their life 

 history and general vitality, and hence in the amount of 

 damage they are able to accomplish. The measures necessary 

 for their eradication vary accordingly. Some wild plants are 

 of so little consequence to economic agriculture that they may 

 be neglected; other species are harmful if plentiful; others 

 may, if they once obtain a sure footing, prove an actual 

 scourge, and involve very great labour, expense and loss; wdiile 

 yet others are injurious or even deadly poisonous to farm stock. 



