54 CLOVER. 



Prevention and Eemedies. — Where Clover Stem- sickness 

 is present, it has been shown, by the experiments of Mr. John 

 Wilhs, at Eothamstead, that an apphcation of a mixture of 

 sulphate of potash 3 cwt., and sulphate of ammonia 1 cwt. 

 j)er acre, had an excellent effect. This was applied April 3rd ; 

 the disease ceased and the Clover made a very vigorous growth, 

 which was continued markedly in the second crop. Sulphate 

 of iron, at the rate of 2 cwt., also answered very well, both in 

 stopping the disease and causing good growth ; but in this 

 case the growth of the second crop was not quite so luxuriant 

 as with the other application. Half quantity of sulphate of 

 iron was less effectual in checking spread of Tylenchus. 



Amongst the series of careful experiments tried for several 

 succcessive years relatively to prevention or cure of Tylenchus 

 attack in Tulip-rooted Oats, or " Stem-sick " Clover, the 

 following mixture acted well : — sulphate of ammonia 4 parts, 

 sulphate of potash 1 part, and steamed bones 2 parts ; this 

 was given at the rate of 1^ cwt. per acre, and was followed up 

 by a dressing of 2 cwt. per acre of sulphate of ammonia. The 

 result gave so luxuriant a growth that in little more than a 

 fortnight after the second dressing the unhealthy plants, 

 if any remained, ceased to be noticeable. 



One very important i^oint to be borne in mind in dealing 

 with attack of this Stem Eelworm is that it infests many 

 kinds of crop and weed-plants, and can pass from one to the 

 other. This may be proved by sowing seed of plants liable to 

 infestation on earth in which pieces of infested stem have 

 been buried. This experiment I have myself tried, and on the 

 broad scale of field cultivation I have notes of Clover-plants, 

 " Stem-sick " from this Eelworm, occurring on land where 

 Tulip-root had been bad in Oats the previous year, and of 

 Tulip-rooted Oats occurring on land where the Clover had 

 been " sick " the previous year. 



It is highly desirable, ivlierc there has been Stem Eelworm- 

 attack, to take as the next crop something ivhich is not known to 

 suffer from it ; and amongst the crops which are especially 

 liable, as Oats are in this country, to attack of the Stem Eel- 

 worm, Clover should never succeed Tulip-rooted Oats, nor Oats 

 Stem-sick Clover. 



The Eelworms have the power of leaving the infested plants, 

 and lie near the surface of the ground ; therefore ploughing 

 with a skim-coulter so as to turn the surface thoroughly well 

 under and to leave it there is a good remedy ; but common 



Dr. J. Ritzema Bos.' Also in my 13th Eeport on Injurious Insects (Simpkin & 

 Co., London) I give a digest of our English observations uj) to date, with a plate 

 showing male and female T. dcvastatrix and eggs, taken, by kind permission, 

 from drawings by Dr. Eitzema Bos. 



