DISEASES OF PLANTS. 569 



throughout the growing season for the prevention of the wilt disease. 

 A fertilizer consisting of 4 parts of potash, 4 of nitrogen, and 1 of 

 phosphoric acid was applied to hills of melons at different times during 

 the growing season, with the result that such plants maintained their 

 vigor, and on the fertilized plats there was no yellowing of vines or 

 spotting of leaves. 



The conclusion was reached that the diseases ordinarily present and 

 abundant in other parts of the field were primarily due to a deficiency 

 of available plant food, and that the indications of actual disease were 

 merely incidental. The fact that where additional fertilizer was applied 

 there was an almost complete absence of the wilt and spotting of the 

 leaves is believed by the author sufficient to warrant further experi- 

 ments along this line. 



Notes on some tomato diseases, F. S. Earle {Alabama College 

 Sta. Bui. IDS, pj). 19-33). — Notes are given on bacterial black rot, 

 bacterial wilt, sclerotium wilt, leaf blights, and leaf mold or mildew. 



The black rot or blossom end rot, as here described, is attributed to 

 an undescribed species of Bacillus. This disease has been under inves- 

 tigation for a number of years, and a preliminary paper upon it was 

 read by the author before the Botanical Club during the meeting of 

 the American Association for the Advancement of Science in 1899. 

 This paper is printed in full, from which it appears that this disease 

 has been known for a long time. It has been usually attributed to 

 attacks of fungi, the principal ones being Jlaerosparmm tomato and 

 Fusariu7n solanL It has been shown by the Vermont Station (E. S. R. , 

 8, p. 992) that these fungi are unable to produce the disease. Toma- 

 toes attacked by this disease show small, irregular, watery areas, 

 usually at the blossom end. Investigations by the author have shown 

 that this region is crowded with bacteria, which have been isolated, and 

 inoculation experiments conducted by which the disease has been 

 readily reduced. The bacillus is of medium size, stains readily, and 

 as yet no spore formation has been detected. It grows readily on the 

 flesh of sound green tomates, causing rot, but can not penetrate the 

 cuticle unaided. It is strictly aerobic, developing only on the surface 

 of culture media. It fails to grow on a number of other plants, such 

 as the fruit of sweet peppers, onions, cabbage, kohl-rabi, etc. Sum- 

 marizing his studies, the author concludes that the cause of the ])lack 

 rot, or blossom end rot, is a bacillus. The method of infection in 

 nature has not been fully determined, but it is probable that it is 

 through the agency of minute insects. The presence of species of 

 thrips in considerable abundance suggested this insect as a possible 

 agency in spreading the disease. When the bacillus is carried deeply 

 into the tomato by an open wound, as is done by the boll worm, the 

 result is a wet rot, qui(;kly involving the entire fruit. In seeking a 

 remedv for this disease, the author believes that insecticides, rather 



