96 WEEDS OF FARM LAND 



are noticed during the winter they should be cut off an inch 

 or two below the surface of the soil with a sharp spade or 

 hoe, and burnt on the spot. If this is impossible the plants 

 should be carried away with the greatest care, in order to 

 prevent seeds or pieces of dodder being scattered about the 

 field. 



If the infection is too widely spread to be dealt with 

 locally, it is best to plough under the affected crop, burying 

 the dodder, provided seed formation has not begun. If seeds 

 are forming the crops should be cut as low down as possible 

 and burnt. As the clover dodder is usually associated with 

 leguminous plants only, it is advisable to avoid growing such 

 crops for a period of years, in order that the dodder seeds 

 lying dormant in the soil may have an opportunity to germinate 

 and die for lack of a suitable host from which they can obtain 

 their nourishment. During this period the land should be 

 cropped with cereals, grasses, or roots, which the clover dodder 

 does not attack. 1 



In some cases spraying is said to be an effective means of 

 eradicating dodder. It is reported that a 1 5 per cent, solution 

 of sulphate of iron kills the parasite and also blackens the 

 clover badly, but that the latter recovers and sprouts again. 

 Arsenite of soda, at the rate of ^ Ib. in 5 gallons of water has 

 proved successful on lucerne. 2 French experiments 3 also 

 show that heavy dressings of sodium nitrate (8 cwts. per acre) 

 will destroy dodder and at the same time strengthen the 

 alfalfa or other leguminous host, thus enabling the latter to 

 resist the drain of the parasite to a greater degree. Sodium 

 nitrate is advantageous in that it does not exercise the 

 same dangerous burning action on vegetation as sulphate of 

 iron. 



BROOMRAPE (Orobanche spp.}, (Figs. 27, 28), Nat. Order 

 Orobanchacece. The lesser broomrape (Orobanche minor] is 

 the species of most economic importance in this country as it 

 fastens on the roots of clover, lucerne, sainfoin, and other 

 leguminous crops and sometimes does considerable damage, 

 completely ruining the second cut of clover in some cases. 

 It also attacks a number of other plants which are not 



1 (1906), " Dodder," Jour, Bd. Agric., XIII, pp. 331-338. 



2 (1908), "Eradication of Dodder," your. Bd. Agric., XV, pp. 280-281. 



3 Farcy, J. (1910), Journal d 1 Agriculture pratique, No. 42, pp. 497-498. 



