DEVELOPMENTS IN HORTICULTURE 33 



method has been quite generally adopted by market gardeners for the 

 production of an early crop. As a result of careful selections 

 through a series of years, in 1917 two wilt- resistant strains of toma- 

 toes were secured. These strains were developed in the badly infested 

 regions of southern Illinois, where the wilt had become a serious 

 menace to tomato culture, and have proved remarkably resistant to 

 this disease, wherever grown. The use of these strains for avoiding 

 loss from wilt, and spraying for control of leaf spot make it possible 

 to grow good crops of tomatoes under adverse conditions. 



DEVELOPMENTS IN FLORICULTURE 



Floriculture is certainly the most attractive division of the sub- 

 ject of horticulture, as well as the most important commercially, tak- 

 ing the country at large, but its difficulties and problems probably 

 outnumber those of any of the other divisions. When one considers 

 the fact that its operations are carried on, not only in the open, but 

 under the most exacting conditions in glass houses, one is confronted 

 with the fact that here arises a new set of problems demanding con- 

 sideration and solution. In 1899, Illinois had not quite seven hundred 

 acres of land devoted to flowering plants, valued at $1,894,960. 

 Looking at the Census report for 1910, with its 1,339 acres of Illi- 

 nois land devoted to flowers; and then in 1920, with 19,626,091 

 square feet under glass and valued at $9,987,606 ; it will be seen that 

 the development in floriculture in Illinois has been a very rapid one. 

 In 1907, the Chief of the Bureau of Plant Industry, placed Illinois 

 as first in the area under glass devoted to commercial flower growing. 

 The retail value of flowers and plants sold in Illinois increased from 

 nearly three million dollars in 1900 to four and one-half million 

 in 1905. 



In the floricultural development at the University of Illinois, 

 some very important results have been obtained in the investigations 

 with fertilizers in their relation to the production of cut flowers. 

 From a three-year project on the effect of acid phosphate, it was 

 found that production can be increased in a profitable way. An in- 

 crease of five per cent in the production both of carnations and of 

 roses, resulted from the application of fertilizers; bulletins have been 

 issued covering these results. From experimental studies made to 

 test the effect of using the same soil in the benches continuously for 

 several years, it was found that the plants grown on the second-year 

 soil were in every way as productive as on new soil. Since 1917, the 

 study with carnations and rose plants to determine the effects of se- 



