THE MONTHLY BULLETIN. 751 



Summary of Control Measures That May Be Recommended. 



In the Orchard. 



At present no entirely satisfactory method of controlling or destroy- 

 ing root-knot is known. 



Carbon Bisulphide.— Where it is the wish to reset young trees in 

 a nematode-infested orchard carbon bisulphide applied to the soil at 

 the rate of 4 ounces per square yard, placed in 8 or 9 holes to the square 

 yard, gives satisfactory results. The holes «hou!d be at least a foot 

 in depth and must be immediately filled after applying the liquid. 

 Carbon bisulphide can not be iised with safety around living trees. 



Fertilization.— Heavy fertilization, together with thorough and 

 deep cultivation, especially if the particular food properties which the 

 soil is poor in be furnished, has been found to greatly improve the 

 appearance and productivity of the orchard. The growth of the root 

 system is stimulated and part, at least, is established below the range 

 of nematode depredation. 



Fig. 397. — Potatoes showing injury inflicted by the eelworm. Tuber on left shows 

 effect on skin : on i i.a:ht, tuber cut open shows colonies of the eelworms on the inside. 

 ( Photo by Bremner. ) 



Flooding.— Flooding can not be recommended in the orchard. 

 Water allowed to stand on the ground long enough to kill the pest will 

 greatly damage, if not destroy the trees. 



Cover Crops. — Susceptible cover crops greatly increase the number 

 of worms ; in view of this fact avoid the planting of .such crops. The 

 iron variety of cowpea or rye can be recommended for the purpose. 



In the Field — No Crops Present. 



Starvation. — The most satisfactory method of ridding the soil of 

 the pest is to keep it free from all vegetation for a period of two years. 

 Allow no weeds to grow — this is a very essential point. 



Nonsusceptible Crops. — The number of nonsusceptible plants is 

 limited. For a winter crop,- plant wheat, rye or barley ; for summer 

 crop peanuts, cowpeas (iron variety) or the velvet bean are recom- 

 mended. Destruction of all weeds is also very essential to the success 

 of this undertaking. The nematode infestation will be greatly reduced, 

 often eradicated hy continuing this process three seasons, 



