34 NUT CULTURE IN THE UNITED STATES. 



pecaii, English [Persian] walnut, and willow, older trees remain stationary a year or 

 so and die with the occasion of a severe drought." 



In a table showing the relative susceptibility of different trees he lists the pecan 

 / among shrubs and trees slightly affected by this disease, and the Persian walnut is 

 numbered among those badly affected. Soil that is annually frozen from 6 to 10 inches 

 deep is found to be nearly free from the worms, especially from those existing in a free 

 state in the soil or inhabiting the soft roots of annual plants, and this may explain 

 why portions of southern Michigan, northeastern Ohio, and New Jersey, with as 

 sandy a soil as Florida or southern Georgia, escape the plague in the peach orchard. 



" My experiments are conclusive that below 50 F. in fluid, and above that when 

 dry, the worms are inactive, paralyzed by cold and shriveled by dryness and heat, and 

 the inference is plain that parties wishing best results must either choose unsus- 

 ceptible stocks for grafting or budding trees liable to infection by the Anguillula, 

 remove to favored locations, or find some means of destroying the worms. After all, 

 I believe the use of trees that are not susceptible to the root knot, for stocks on which 

 to graft or bud the susceptible varieties, is the proper solution of the root-knot prob- 

 lem. The matter of location, soil, fertilizer, and prevention, then, need not worry 

 the intending orchardist. Find the disease-proof tree and the thing is done, and most 

 of my experiments have been directed in some measure to secure this result. Some 

 seedlings of our American plums are destined to replace the peach as a stock unless 

 the Japanese variety proves superior. I have found nothing of value for the English 

 [Persian] walnut nor for the weeping willow." 



J In response to our inquiries concerning nut stocks that resisted the attacks, Dr. 



Neal replies: "The black walnut grew tolerably well when the Persian walnut tree 

 was a complete failure, and I expect if it were planted on new land where the trees 

 were to stand, and then budded or grafted, there would be a good chance to make it 

 a success. As a rule, trees and plants that are introduced are more susceptible to the 

 ravages of these worms than are the native kinds." So far as it is known, no experi- 

 ments have been made with the California walnut as a stock in regions affected by 

 root knot. This should be tested, and the congeniality of the pecan and other hicko- 

 ries as stocks for the walnut should be determined, since they are known to be free 

 from injury or but slightly affected. It is not unlikely that some of the Southern 

 hickories will be found congenial. A. H. Norris, of Morganville, N". Y., who has a 

 place at Spring Garden, Fla., informs us that he grafted a few years since a number 

 of Persian walnut scions into hickory trees (probably Hicoria alba Britton, Carya 

 tomentosa Nutt.) that had just been transplanted. Concerning this experiment the 

 postmaster at Spring Garden, to whom a letter of inquiry was addressed, replied : " I 

 went in person and saw eight or ten walnuts growing in hickories. The branches of 

 the walnut were from 1 to 4 feet in length. The grafting was done from one to three 

 years ago. There is no doubt that they will grow, but the percentage that will live 

 by grafting will be small, about 25 per cent." From statements made by Mr. Norris 

 concerning the number of scions set, we believe it is an overestimate that 25 per 

 cent of the grafts thus set succeeded. Successful grafting of a newly set tree is 

 exceedingly difficult, and in the case of so stubborn a stock as the hickory it has 

 rarely been accomplished. A much more promising method would be that of grafting 

 at the crown and banking with earth, as described under "Crown grafting" (p. 15). 



Selection of seed. If seedlings are to be depended on for fruit without the inter- 

 vention of budding or grafting, it is important that proper care be taken to select 

 such nuts for planting as are likely to produce a marketable product. The tendency 

 among those growers who have given the matter of seed selection special attention is 

 to select for seed the largest nuts with the thinnest shells, and that is now the pre- 

 vailing practice. It may well be questioned, however, whether a thinner-shelled nut 

 than many of those now marketed from California is desirable. A firm shell of 

 medium thickness seems desirable in the walnut, both to prevent breakage in ship- 



