132 MISC. PUBLICATION 43 4, U. S. DEPARTMENT OF AGRICULTURE 



damage. A better method, however, of preventing outright killing 

 of the stock consists of ridging soil against the trees in the fall. At 

 the time of the last cultivation, the throwing of a 3- or 4-inch ridge of 

 soil against the stems of the seedlings will insure protection of the root 

 crown against injury. Such hilling-up may be easily accomplished 

 with a disk-shovel attachment to the cultivator. 



Losses Occurring After Lifting 



The losses which occur after the nursery stock has been dug are 

 influenced by weather conditions, such as drying or freezing, but are 

 chiefly due to human failure to take the necessary precautions. 



Since the handling of deciduous stock in distribution does not re- 

 quire the painstaking care to avoid exposure of the roots of the seedling 

 that is necessary with conifer stock, the 10 to 15 minutes required in 

 the distribution procedure already outlined allows an ample margin 

 of safety. 



Occasionally shriveled roots and bark indicate seedlings that have 

 been unwittingly exposed in transit or in handling to such a degree that 

 injury from drying has resulted. This does not necessarily mean that 

 the seedlings are dead or need be discarded. If the stock is covered 

 with moist packing material for several days and soaked down with 

 water or buried in moist soil for several days or the roots are placed in 

 fresh water, the trees may absorb sufficient moisture to revive. If 

 the stock has not been dried too much, the cells will again become 

 turgid and the seedlings will have most of their normal vigor restored. 

 If the seedlings do not return to their normal condition after several 

 days and the roots begin to discolor and slough off, the trees are dead 

 and should be discarded. 



It is well known that the roots of plants are more subject to injury 

 by freezing than the tops, and freezing of the roots of seedlings at some 

 point during the handling process is a common cause of damage. 

 Frozen stock should be thawed out gradually, with as much moisture 

 present as is possible and with a minimum of handling. Properly 

 thawed out, they will in many cases show no evidence of injury. If 

 injury has occurred, it can sometimes be detected by a discoloration of 

 the cambium layer of the roots. If the frozen stock is on a truck, the 

 safest procedure is to drive the truck into a cool shed (40° to 60° F.), 

 add additional packing material, sprinkle with cold water, and allow 

 to thaw out over a period of several days. Cold water added from 

 time to time will assist in drawing the frost from the trees. It is 

 advisable to heel-in such seedlings in moist soil for a week. If the 

 injury is slight, a normal or healthy appearance will be restored, 

 whereas if the injury has been fatal, rotting and discoloration of the 

 roots will be evident. 



Insects Feeding on the Roots 17 



Some of the most dangerous pests of those most likely to cause 

 damage to hardwood stock in plains nurseries, and the most difficult 

 to control are insects that feed on the roots. White grubs and 

 termites are among the worst offenders; wireworms and borers cause 



17 The following sections on nursery insects and their control are contributed by J. A. Beal, entomologist, 

 L. G. Baumhofer, associate entomologist, and N. D. Wygant, assistant entomologist, Bureau of Entomology 

 and Plant Quarantine. 



