554 DISEASES OF CULTIVATED PLANTS 



present seedling tea plants have alone been injured, but its 

 presence has also been observed on the roots of old bushes. 

 On seedlings, nodulose swellings are formed on the root just 

 below the collar. One of the most serious points about the 

 eelworm is the fact that in affected areas it attacks nearly all the 

 weeds as well as the tea. It appears to be specially prevalent 

 where villages and village gardens have previously existed. 

 In a case investigated in Darjeeling the land had been under 

 cultivation for a long period. Dirty land and neglected 

 clearances are also just the places in which those weeds 

 which are peculiarly susceptible to the disease will be likely 

 to grow, and pass on the eelworm to the tea. 



The most important preventive method is to rid the land 

 of all weeds capable of providing the eelworm with food. 

 This should be followed by planting a trap-crop of some 

 plant the eelworm will readily attack, and removing such 

 plants before the eelworm s pass from the plants into the 

 soil. The second method is to starve the eelworm by 

 allowing the land to lie without a crop for a year, or by 

 growing a crop not attacked by the pest. In the hills, 

 buckwheat would answer this purpose. Complete success 

 has also been claimed by drying out the surface soil by 

 constant cultivation in the dry weather for a season. 



Watt, Sir George, and Mann,-H. H., The Pests and Blights 

 of the Tea Plant, Ed. 2 (1903). 



Eelworm disease of oaks. A destructive epidemic of 

 young oaks is recorded from France. The pest is Hetzrodera 

 radicicola (Greef), which attacks the root more especially in 

 the region where mycorhiza are present. 



Ducomet, Ann VEcole nat. d'Agric. Rennes, 1909, p, 47. 



Eelworm disease of coffee. A root disease of coffee has 

 long been recognised in the coffee plantations in Brazil, 

 although the true cause has only recently been determined. 

 A similar disease has recently been recorded from Costa 

 Rica, and I have reasons for suspecting its occurrence in 

 other coffee-growing districts in the New World. The 

 characteristic symptoms of its presence depend on the age 

 of the tree. When the tree is fairly old the leaves on young 

 shoots turn yellowish-green and shrivel, the young shoots 

 also blacken and wilt. This condition of things may 



