May 6, 1896.] 



Garden and Forest. 



189 



First: The " late blight " or mildew caused by the fungus 

 Phytophthora infestans. 



Second: The "early blight," Macrosporium disease, or 

 " leaf spot" disease, due to the parasitic attacks of the fungus 

 Macrosporium Solani, E. & M. This is characterized by the 

 appearance of numerous sharply defined dark spots scattered 

 irregularly over the leaf. These spots, enlargingslowly, dry, and 

 the tissue is by this drying thrown into irregularly concentric 

 elevated rings. The character of these rings is peculiar, and 

 forms a valuable method for hasty identification of the disease 

 as it usually occurs. These spots may or may not originate 

 from flea-beetle punctures. It is agreed by all investigators 

 that this fungus most readily attacks plants or leaves that have 

 passed their period of greatest vigor. It is, as Dr. Sorauer 

 says, one of the " Schwacheparasilen," but, nevertheless, a 

 most destructive parasite when well established in a field. 



Third : " Tip-burn," a disease characterized by the drying of 

 the leaves at the tips and margins, not necessarily associated 

 with any fungus attacks, but attributable to physiological con- 

 ditions surrounding the plant, especially to dry hot weather 

 with insufficient water-supply, and aggravated by insect attacks 

 or any other conditions which lessen the vigor of the plants. 

 This is clearly the trouble figured in the Cornell bulletin as 

 '* early blight." Mr. Lodeman's account of the physiological 

 conditions leading to this disease is excellent and in accord 

 with my own observations, but, as already indicated, we must 

 clearly distinguish this third disease from the second, both as 

 to cause and appearance. Of course, various fungi and bac- 

 teria capable of existing as saprophytes soon invade the tissue 

 which has died from "tip-burn," and these soon complicate 

 and often aggravate the disease. As shown in the material 

 examined, the nature and extent of these secondary fungus 

 invasions varies considerably in different localities according 

 to conditions. These invading fungi are exceedingly interest- 

 ing, and have received considerable study ; a discussion of 

 them would, however, be out of place in the present sum- 

 mary. 



Fourth: " Arsenical poisoning " from Paris green or other 

 arsenites applied as insecticides. In case of extremely strong 

 application of these arsenites the leaf may be entirely killed or 

 large areas " burned " within a short time. Usually, however, 

 its action is slower and longer-continued. Its effects are then 

 apparent as dead spots centering about flea-beetle punctures 

 or other mutilations in the leaf. These spots continue slowly 

 to enlarge for some time, and, as a result of the slow death and 

 drying of the tissues, the surface of each is thrown up into 

 distinctly concentric elevations or ridges forming " ringed 

 spots" so similar to those caused by the attacks of Macrospo- 

 rium Solani that they are extremely deceptive. There is, 

 however, a distinctly different color to the spot, as a rule, and 

 the rings are more regularly circular in the poisoned spots. 

 These arsenical poisonings are of very common occurrence, 

 and are unquestionably responsible for much of the confusion 

 regarding "early blight." 



Fifth : Dead spots sometimes occur on the margins of leaves 

 or surrounding flea-beetle punctures or other injuries which 

 are not invaded by fungi, and do not seem attributable to 

 arsenical poisoning. They develop the characteristic rings, 

 and resemble spots caused by the Macrosporium or the arsen- 

 ical poisoning, but are often, at least, due to dry heat, as sug- 

 gested by Dr. W. C. Sturgis in the Report of the Connecticut 

 Experiment Station for 1894. In this case they should be asso- 

 ciated as to cause with "tip-burn" rather than with "early 

 blight." 



Experiment Station, Burlington, Vt. L. R. yones. 



Recent Publications. 



Nut-culture in the United States. United States Depart- 

 ment of Agriculture. 1896. 



Six years ago Professor H. E. Van Deman, who was at 

 that time Pomologist of the Department of Agriculture, 

 sent out circulars of inquiry to all parts of the United 

 States where there have been any systematic efforts 

 at planting nut-bearing trees for the production of their 

 fruit. Wild nuts have always been so abundant in this 

 country that there has been little need of cultivating the 

 native sorts. Our native pecans, shellbarks, walnuts and 

 chestnuts vary widely in size and quality, but it has been 

 the popular belief that a long time would be required to 

 raise the improved varieties in any quantity, since propa- 

 gation is slow and grafting in many instances difficult. 



Nevertheless, there have been many individual instances 

 where success has been won with improved kinds of our 

 native Chestnuts and the foreign sorts, with the English or 

 Persian Walnut, with the Almond and the Pecan, and there 

 have been hopeful experiments with the Shellbark Hickory 

 and in the extreme south with the Cocoanut. A very good 

 account of what has been really accomplished will be 

 found in this book, which is a compilation of the answers 

 to the replies made to Professor Van Deman's circular, and 

 published by the Department of Agriculture. The text 

 makes about one hundred quarto pages, to which are added 

 sixteen full-page plates, some of them colored, and there is 

 a carefully prepared index. The cultivation of the Almond 

 is already established in southern California, and seedlings 

 of excellent quality are constantly produced, and it seems 

 to have become a matter of common observation that the 

 best variety in any locality is some seedling which origi- 

 nated there. The cultivation of the Persian Walnut, too, 

 has become well established in southern California and the 

 exports are increasing annually. Perhaps the largest cul- 

 tivated Walnut grove in the world is one in California, 

 which contains seven hundred acres. The account of 

 hybrids between different species of Walnut from eastern 

 Asia with the California Walnut, our Black Walnut and the 

 Persian or English Walnut suggests the possibility of pro- 

 ducing trees of widely varying form and habit, although 

 no distinct improvement in the fruit has yet been accom- 

 plished. 



Perhaps the most interesting chapter in the book is that 

 on the Hickory, especially the section which relates to the 

 Pecan, a tree which equals in importance, if it does not sur- 

 pass, the Persian Walnut and the Almond. This tree will thrive 

 over a large area and the fruit varies very considerably, 

 so that by selection it is possible to get large, thin-shelled, 

 delicately flavored nuts. Large orchards are being planted, 

 and in many cases trees which bear inferior nuts in the 

 forests are cut out so as to leave room for those which bear 

 better ones. A grove of this sort — that is, a grove made by 

 thinning out a forest of 450 acres on the Guadaloupe River, 

 in Texas — has produced $2,000 worth of nuts in a year. 

 One of the plates represents a wild Pecan-tree which 

 had been top-budded four years earlier with five choice 

 varieties, and it already shows a vigorous head of young 

 shoots bearing nuts. If this method is practicable with 

 large trees it will not be difficult to utilize the abun- 

 dant wild trees of the south for the production of choice 

 nuts. A good account of the experiments with Shell- 

 barks is also given, and the story of the improved 

 • varieties of Chestnuts, with which the readers of this 

 journal are familiar, is told at length. It seems proba- 

 ble, too, that from Delaware southward the English Hazel- 

 nut can be successfully grown, and there are some of 

 our native Hazels in the north which bear nuts as large 

 as imported filberts, with thin shells and altogether of supe- 

 rior quality. Many of the species of Pine on the Pacific 

 slope, including Arizona, have seeds that the Indians use 

 as food, and they are marketed in large quantities in some 

 of the cities of California. One of the plates of this book 

 is devoted to the seeds of these Pines, twelve different sorts 

 being figured. Some of them are large, soft-shelled, of a 

 delicious flavor, so that they are valued both for dessert 

 and confectionery purposes wherever they can be had. 

 These nuts are generally harvested by the Indians, who 

 heat the cones until they rattle out, having been roasted in 

 the process. Whether any of these species will reward the 

 planter if brought into cultivation is a matter of the merest 

 conjecture. 



Little needs to be said of the miscellaneous nuts, native 

 and imported, several of which are grown in a small way in 

 different parts of the country. The general subject, how- 

 ever, is most interesting, and this bulletin is valuable for 

 bringing together in a condensed form about all that is 

 known of it at the present time. The truth is, that the sum 

 total of our knowledge is now very slight indeed. Few 

 fields offer greater attractions to the workers in our experi- 



