628 ANNUAL REPORTS OF DKPARTMENT OF AGRICULTURE. 



inj; and ljir<j;r yichls of potatoes Ixivo Ixm'Ii obtained on soil thus 

 treated. The hest results were obtained with steamed soil and with 

 soil treated with Bordeaux mixture and with mercuric chloride. 

 Further tests of such soil treatments are in progress. 



MiscEiJ.AXEous RESEAiu'ii NOTES. — It has bccn shown that the 

 soils in the infested gardens are coininonly very acid, and tliat infec- 

 tions are less severe where tlie soil reaction approaches neutrality. 

 The organism lias been shown also to l)e an acid producer in the 

 tissues it infects. 'Hiese facts indicate the desirability of more exten- 

 siv(^ studies on the re\ation of soil reaction to distribution of and 

 infection by this organism, and such studies are projected for the 

 coming winter. In general it is planned to study more intensive}}'" 

 than heretofore tlie soil environment and the meteorological charac- 

 teristics of the infested areas witli a view to correlating with these the 

 present and possible distribution of the wart disease in the United 

 otates. 



The majority of the tomato varieties tested for reaction to the 

 wart disease became infected and it seems probable that the tomato 

 may not show the varietal differences in susceptibility and resistance 

 so characteristic of the potato. ^^Tiile the tomato is not affected in 

 yield by this disease, its service as an additional host makes it a fac- 

 tor to be considered seriously in a i)otato quarantine program. No 

 new hosts have been definitely determined for this organism, but 

 several solanaceous plants are under suspicion and a number of new 

 species will be tested this winter. 



In cooperation with the department of botany of Pennsylvania 

 wState College a method has been worked out of isolating wart spo- 

 rangia from the soil, either singly or in quantity. This method will 

 be of great service in further investigations on the germination, 

 thermal, and toxic relations, etc., of the organism. 



COOPERATION WITH OTHER BUREAUS IN ADMINISTRATION OF PLANT QUARANTINES 



In addition to the corn borer, Japanese beetle, and the gipsy moth 

 and brown-tail moth quarantines carried out in cooperation with 

 the Bureau of Entomolog}^, the board is cooperating with the Bureau 

 of Plant Industry in the enforcement of the quarantine on account 

 of the black stem rust of wheat and the quarantine on account of 

 the white pine blister rust. The board is also cooperating in the 

 enforcement of the State quarantines on account of the flag smut 

 and take-all diseases of wheat, as well as enforcing the foreign quar- 

 antines promulgated by the board on account of these diseases. 



COTTON. COTTON WASTE, COTTON BAGGING. AND COTTONSEED PRODUCTS 



IMPORTATIONS. 



The restrictions on the entry of cotton, cotton waste, burlap, 

 cotton seed, seed cotton, and cottonseed products for the purpose 

 of excluding the pink bollworm and other pests is a part of the con- 

 tinuing work of the board and represents a large element of the port 

 inspection service at the ports of entry where such importations 

 are authorized. These ports are Boston, New York, San Francisco, 

 and Seattle. No restrictions are placed on the entry of cotton from 

 Lower California, Mexico, under a cooperative arrangement with 

 the authorities of that State, except that it must come in under 

 permit through the port of Calexico. By special arrangement, 



