cherry, peach, or nectarine plantings for a distance of 500 feet. 

 Removal to a shorter distance, although not as effective, will be 

 beneficial. Dr. M. Wayne McKee, Hudson Valley Laboratory, stated 

 that preliminary results indicate that spread of X-disease can be 

 reduced to as low as 1°/ tree loss by eradication of chokecherry and 

 applications of insecticide sprays during September and October to 

 control the leafhopper vector of X-disease. The sprays are essen- 

 tial because the highest populations of leafhopper vectors are pre- 

 sent on peach trees in September and October when insecticides are 

 not ordinarily applied. 



The peach replant problem . Dr. P. A. Arneson, Extension Pathologist, 

 Cornell University, stated that there is a high rate of mortality 

 of newly-planted peach trees in the Hudson Valley. Examination of 

 these orchards showed that the problem is more related to the "peach 

 replant problem" than X-disease. The young trees often were planted 

 where dead trees had been removed, or else a new planting had been 

 established immediately after removal of old trees. The trees ap- 

 pear weak and many die shortly after planting. The symptoms of the 

 peach replant problem as described by Dr. Arneson are retarded 

 growth, shortened internodes, and reduced yields if the trees come 

 into bearing. 



The replant problem is considered a complex of problems with 

 several contributing factors: (1) poor soil structure; (2) low 

 soil fertility; (3) toxic chemicals leached from decomposing peach 

 roots; (4) pathogenic fungi; (5) pathogenic bacteria; (6) stem-pit- 

 ting virus; and (7) nematodes. One or more of these factors could 

 be the cause of tree mortality and/or low vigor in a peach orchard. 

 The following are suggestions by Dr. Arneson for preventing replant 

 probl ems . 



"In sites where the populations of the root lesion nematode are 

 high, the soil must be fumigated. For proper fumigation, the land 

 must be plowed and fitted to seedbed condition, that is, the soil 

 must be loose and free of large clods to a depth of at least 10 

 inches. This should be done well in advance of fumigation to allow 

 adequate time for decomposition of the organic matter. Soil temper- 

 atures must be above 50°F for proper fumigant action. Therefore, 

 the fumigation should be done from about mid-August to mid-October 

 of the year before the trees are planted. This is to assure ade- 

 quate time for the fumigant to dissipate before the spring planting. 



The newly planted trees cannot be simply ignored until they 

 begin to produce a crop. The first 3 years are the most important 

 ones in the life of a young peach tree. Careful attention to fer- 

 tilization, ground cover management, pruning, training, and pest 

 control at this time will reap benefits throughout the production 

 life of the orchard." 



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