BUREAU OF PLANT INDUSTRY. 157 



large number of States. It has been distributed this season to a 

 limited extent in all the States where the greatest losses occur and is 

 being increased for larger distribution next j'ear. Other varieties 

 which are even more promising in disease resistance and which have 

 been bred to fulfill special market requirements are being tested and 

 propagated this year. 



Previous efforts to control the Septoria leaf-spot of tomatoes, 

 which causes losses amounting to several millions of dollars annually, 

 by the use of standard Bordeaux mixture and ordinary spraying 

 methods have given not only irregular results, but in the majority 

 of cases unprofitable returns. A new resin-fishoil soap Bordeaux 

 mixture applied by improved methods has given excellent results in 

 the control of this disease and is being used by growers in a number 

 of localities this year. In preliminary experiments in Florida Al- 

 ternaria leaf-spot of tomatoes was successfully controlled by spray- 

 ing with standard Bordeaux mixture. Investigations of the diseases 

 attacking Florida winter-grown tomatoes, with particular reference 

 to their development in transit to market, have shown clearly which 

 of these diseases develop and spread in transit and thus where reme- 

 dial measures must be applied' for their control, 



PATHOLOGICAL ADVISERS FOR COTTON, TRUCK, AND FORAGE CROP DISEASES. 



During the year extension pathologists were located in 19 States. 



The demonstrations on the control of cotton wilt, which have been 

 in progress for several years, resulted last year in the planting of a 

 larger acreage to wilt-resistant cotton than ever before, with an 

 actual saving greatly in excess of that of any previous year. Two 

 cotton planters in South Carolina report that their saving last year 

 through growing wilt-resistant cotton was approximately $115,000. 



Demonstrations of methods of control of sweet-potato diseases 

 in Accomac County, Va.. last jea.r resulted in a benefit to this county 

 alone of about $100,000, due to the application of the control methods. 

 Special efforts were made during the bedding season this spring 

 which resulted in the location and distribution of a considerably 

 larger quantity of disease-free roots than would otherwise have been 

 used for bedding purposes. A campaign for the selection of disease- 

 free seed stock in the field and the storing of the sweet-potato crop 

 under proper conditions is now under way. 



A large saving to watermelon growers in central Georgia was 

 effected last season through the assistance given them in the applica- 

 tion of methods for the control of anthracnose and Diplodia end-rot, 

 two important causes of deterioration in melons en route to market. 



Seed surveys conducted in cooperation with other branches of the 

 department resulted in the locating of considerable quantities of an- 

 thracnose-free beans and potato seed stock comparatively free from 

 disease. Active work is now under way on the demonstration of 

 methods for the control of potato late-blight and the location of 

 disease-free fields for seed stock. 



The facilities of the extension organization have also been used 

 in the distribution of the rust-resistant strains of asparagus, which 

 have now been placed in the hands of the county agents in practi- 

 cally all the asparagus-growing States. 



