254 Peach-Growing 



prerequisite for successful peach-culture in regions where 

 nematodes are prevalent. Since many vegetables and other 

 economic plants are susceptible to nematodes, they should 

 not be used as interplanted crops on land free from nem- 

 atodes in sections where they commonly occur. Clean 

 cultivation should be followed, since many weeds also are 

 subject to nematodes. Most varieties of cowpeas are 

 attacked by the nematodes, and many growers are reluctant 

 to use this crop for maintaining the fertility of the soil 

 where otherwise they could be grown in an orchard with 

 great advantage to the trees. However, the Iron and 

 Brabham varieties of cowpeas are practically immune to 

 nematodes, hence may be used with comparative safety, 

 as described in the chapter on cover-crops. 



Land that becomes infested with nematodes can be freed 

 from them only by starvation treatment, either by pre- 

 venting all vegetation from growing for a sufficient length of 

 time or using a rotation of crops all of which are immune 

 to them, but obviously this method is impossible of applica- 

 tion in a peach orchard. 



By using nitrogenous fertilizers and making the soil 

 very fertile, an infested peach orchard, if the trees have 

 previously become well established, may sometimes be made 

 to thrive fairly well, provided other conditions of growth 

 are favorable. 



An effective method of rendering infested soil compara- 

 tively free from nematodes has recently been described by 

 Watson,^ which consists of applying "cyanamid" or cal- 

 cium cyanamide to the soil, followed by irrigation, but the 

 expense of this material in the quantity in which it has to 

 be used, and its injurious effects for a time on the soil, are 

 1 Fla. Agr. Exp. Sta. BuU. 136, 



