1909.] 



The Eradication of Dodder. 



209 



In connection with the eradication of the clover parasite, 

 Dodder, an article on which appeared in this Journal 



for Sept., 1906, p. 331, the Board have 

 The Eradication received some interesting notes from 

 of Dodder. Captain S. M. Smith, who has made 



some experiments with a view to sup- 

 press dodder on his farm near Birchington. The clover was 

 sown in 1907 on a thin barley crop, and came up an "extra- 

 ordinarily fine thick plant," but was attacked by dodder, 

 locally known as Hell- weed. Patches were first scarified with 

 a rake, and the dodder appeared to die down, but after subse- 

 quent cutting of the clover it was found that the dodder ten- 

 drils were plentiful, and scarifying alone was concluded to be 

 "absolutely useless." In their Leaflet No. 180, the Board 

 condemn tearing out the dodder with a rake, and this advice 

 was found to be quite sound. Dressing the patches with 

 calcium sulphide was not practicable on account of the pro- 

 hibitive cost of the material, 1 cwt. covering only about 

 10 perches. Moreover, it was not found to have any good 

 result. The use of lime was also unsuccessful. 



In 1908 clover ("seeds") was sown on a seven-acre field, 

 and again dodder made its appearance, and Captain Smith 

 remarks that "it is astonishing how very quickly the rings 

 are formed. It reminds one of Tinea tonsurans (ringworm) 

 on young cattle and horses in the manner it thrives and its 

 rapidity of growth." In neither 1907 nor 1908 was the attack 

 due to impure seed, since seed from the same bulk sown on 

 a neighbouring farm was not infested. The plan then tried 

 consisted in removing the surface of the affected spots with a 

 plate-spade and burning the material (earth, dodder, &c.) 

 mixed with old thatch in the centre of each patch, followed 

 by burning a layer of waste 'straw on the top of the cleared 

 patches, taking care to put it well on the edge, even sacrificing 

 a portion of the unaffected crop round the edge. This plan 

 was carried out in September, 1908, and appears to have been 

 entirely satisfactory, and Captain Smith, writing in May of 

 the present year, states that "there is now no sign of the 

 dodder on the growing clover." 



The infested patches treated in 1908 were twenty-five in 

 number, and from three to six paces in diameter, whereas 



Q 



