1919] HORTICULTURE. 45 



Applications of complete fertilizers, although showing Increased yield over 

 check plats, were less beneficial than applications of nitrate alone. It is 

 pointed out, however, that on the lighter soils, especially where water-holding 

 capacity and fertility are often poor on account of lack of humus, commercial 

 fertilizers should not be used to the exclusion of green manures, stable manures, 

 etc. Summer applications of fertilizers appear to possess considerable merit 

 as compared with those made in the spring. Where combined fertilizers were 

 used, late summer applications gave somewhat larger berries than spring appli- 

 cations of similar fertilizers. 



Currants and g'ooseberries, G. M. Darrow {U. S. Dept. Agr., Farmers' Bui. 

 1021t (1^19), pp. 40, figs. 26). — This discusses the essential features of currant 

 and gooseberry culture, the selection of varieties, uses of the fruit, and the 

 regions in which these plants may be grown. Certain restrictions on their cul- 

 ture due to such insect pests and diseases as the currant maggot and blister 

 rust, have been pointed out. 



In view of the fact that blister rust, so destructive to white pine trees, 

 passes one stage of its growth on currants and gooseberries, it has been found 

 necessary to destroy all currant and gooseberry bushes in certain areas, and 

 to prohibit the further planting of them in certain areas representing valuable 

 lumber interests. The laws which have been enacted by the several States to 

 this end and the Federal quarantine regulations respecting the interstate ship- 

 ment of currant and gooseberry plants and pine-tree nursery stock are here 

 explained. 



The avocado in Guatemala, W. Popenoe (U. S. Dept. Agr. Bui. 743 {1919), 

 pp. 69, pis. 23). — An account of the avocado in Guatemala, with reference to 

 its importance, extent of culture, popular uses, and types of avocados grown. 

 Avocado culture in the Guatemalan highlands is discussed with reference to 

 the origin of choice varieties, soils, growth and habits of the tree, cultural 

 practices, regularity of bearing, yield, season, picking, ripening, and marketing 

 the fruit, variation in fruits, climatic conditions in the principal avocado 

 regions, hardiness of the avocado, and enemies of the avocado. 



An account is also given of the coyo, a distinct species of Persea resembling 

 the avocado, which possesses a distinctive and agreeable flavor and is con- 

 sidered superior to the avocado in some parts of Guatemala. Some 23 Guate- 

 malan avocados, introduced by the Office of Foreign Seed Plant Introduction 

 into the United States for trial in California and Florida, are de.scribed. 



Vanilla. — -A promising new crop for Porto Rico, T. B. McClelland {Porto 

 Rico Sta. Bui. 26 {1919), pp. 32, pis. 3, figs. 4). — This bulletin embodies the 

 results of investigations conducted by the station for several years with a view 

 to establishing the vanilla industry in Porto Rico. 



Introductory considerations deal with the general status of the vanilla indus- 

 try and market prospects. The history is given of the experimental planting at 

 tl'.e station, including directions for starting a vanillery, propagation, shading, 

 care of plantation, methods of hand-pollinating the blossoms, picking, curing, 

 and prep;iration for market. 



The expciimeuts conducted at the station have resulted in the production of 

 vanilla beans pronounced by dealers as excellent in quality. The crop from a 

 small plat, which was marketed at less than four years from the time the 

 cuttings were set, averaged about i lb. cured beans per fruiting vine. The 

 gross returns from the sale of this crop were at the rate of a little less than 

 $400 per acre. In the following year the yield increased to ^ lb. cured beans 

 per vine, and the estimated gross returns based on samples submitted to dealers 

 was from $700 to $900 per acre. In the third harvest year the crop from these 



