1919] HORTICULTURE. 145 



seasons and has been found to be reasonably satisfactory in field practice. 

 Some representative results secured in field trials are given, together with 

 directions for using the method. 



In making the test " a 200 gm. fresh weight sample of leaves is washed at 

 least 3 minutes, with occasional stirring, in 1,000 cc. of a 0.2 per cent solution 

 of chemically pure nitric acid in water, either distilled or sufficiently pure to 

 give correct results. A convenient amount of this acidulated wash water is 

 treated with a few drops of 2 per cent solution of potassium-ferrocyanid solu- 

 tion, sufficient to precipitate the copper. A color comparison is then made 

 with a series of known dilutions of a standard copper solution, similarly treated 

 with the potassium-ferrocyanid solution. From this comparison the copper 

 content of the wash water is determined. For more exact readings a color- 

 imeter may be used." 



The test promises to be of value to pathological investigators, agricultural 

 experts, and commercial growers, " to secure data showing the persistence of 

 copper-containing sprays as it luay be influenced by method of preparation, 

 weathering, or other factors; to determine the minimum and maximum limits 

 of working safety zones, as measured by evenly distributed residues, effective 

 for the practical control of specific diseases; to secure prompt correction of 

 faulty spraying practices, either in the preparation of mixtures or in the times 

 or modes of application, with a view to insuring more effective and economical 

 protection of crops ; and to serve as a practical guide in timing new applica- 

 tions, especially after rainy periods." 



Keport of horticulturist, C. A. McCue {Delaxvare Sta. Bui. 122 (1918), pp. 

 25-28). — A brief statement of progress made in various lines of work. 



Variety tests of orchard and small fruits were continued. A list is given 

 of peach varieties recommended for commercial plantings and those which 

 have been rejected as having no value as commercial varieties. In the variety 

 test of cherries Montmorency and various strains of this variety have proved 

 most valuable for Delaware. It appears doubtful whether the sweet cherry 

 will be valuable in Delaware orcharding. 



Cover-crop studies in peach orchards have been completed. The results in- 

 dicate tliat under Delaware conditions the cowpea is one of the best, if not 

 the best, cover crop for peaches, but that no one cover crop is always best in 

 a given peach orchard. The light and shade factor has an important bearing 

 upon cover cropping. The soy bean is a valuable cover crop and oats is also 

 recommended. Rape and cowhorn turnips may be used for the first three 

 years, but not afterwards. Winter vetch is not a good cover crop for northern 

 Delaware. It is concluded that in most cases sufficient nitrogen for good 

 growth and yield of peaches can be supplied by proper cover cropping with 

 leguminous plants, providing the cover crop is begun early in the life of the 

 orchard and is continuous. 



[Beport on horticultural investigations] {Geor(/ia Sta. Rpts. 1917-18, pp. 

 11-13). — Brief statements of progress made with various projects. 



As a result of the coUard breeding work a new commercial type has been 

 established and the seed introduced to the trade. In the work of breeding 

 and selection for a tomato resistant to blossom-end rot. Fa generation plants 

 resulting from a cross between the Red Cherry and the Greater Baltimore 

 varieties proved to be susceptible to the blossom-end rot. Since previous 

 filial generations of these plants, partaking more of the Cherry type, were im- 

 mune to the blossom-end rot it appears that susceptibility has returned with 

 increased size in the process of selection. 



A considerable number of hybrids secured in the grape-breeding investiga- 

 tions produced their first fruit in 1918. It was observed that one white stami- 



