788 EXPERIMENT STATION RECORD. 



Soaking seed in both copper sulphate and formaldehyde was injurious to germina- 

 tion, while the seed subjected to the hot-air treatment not only produced the great- 

 eel number of plants but also the highest number of heads of wheat. The effect of 

 the treatment on the smut is not stated. 



Earcockle in wheat, R. Helms {Jour. Dept. Agr. West. Australia, 10 (1904), No. 

 1, pp. 34-38, figs. ' \. — A description is given of a disease of wheat and other cereals 

 which is caused by attacks of the nematode Tylenchw Iritiei. These nematodes by 

 reaching the newly formed heads attack the reproductive organs, damaging and 

 destroying them. A.s a consequence, no seed is formed, but instead galls are pro- 

 duced which serve as a shelter for the young nematodes. 



The larva:- are said to retain their vitality for a long time, and a brief experiment 

 shows that repeated drying and exposure to hot sunshine for 18 days did not affect 

 their vitality. Other experiments seem to indicate that they may be revived after 5 

 or more years' suspension. 



In combating this trouble, which is becoming serious in parts of Australia, rotation 

 of crops is recommended, care being taken not to introduce other cereals or certain 

 grasses, as they are subject to attack. Where wheat is sown, it is suggested that it 

 should be treated with fungicides for the prevention of fungus attacks, and this 

 treatment will cause the lighter-infested grains to float so that they may be readily 

 skimmed from the fluid. 



Potato diseases, H. H. Hume (Florida Sla. Bui. 75, pp. 181-196, figs. 7). — Descrip- 

 tions are given of a number of diseases of potatoes which have been observed by the 

 author as occurring more or less seriously in Florida. The disease which attracts 

 most attention is the late blight (PJiytophihora infestans), a description of which is 

 given, and the effect, as shown by the yield in various regions, is indicated. This 

 disease is believed to have been introduced recently into Florida in seed potatoes. 

 As methods of control the author suggests the exercise of care in securing the seed 

 potatoes, and thorough spraying with Bordeaux mixture, 5 or 6 applications to be 

 given the plants. 



Notes are also given on the early blight (AUernaria solani), potato -cab i Oospora 

 scabies), and the Rhizoctonia disease. This last disease is said to be widely distrib- 

 uted in Florida, and a careful examination made of seed potatoes offered for sale by 

 different dealers failed to show a single lot which did not contain the sclerotia of the 

 fungus on some of the tubers. Experiments in controlling this disease were carried 

 out, in winch the seed tubers were treated with corrosive sublimate, copper sulphate, 

 formalin, phosphatic slag, and lime in various amounts. 



The largest yields were obtained where the potatoes had been exposed to the li^l it 

 and air until they became quite green and then planted, while the plat receiving lime 

 at the rate of 1 ton per acre and the seed treated with formalin was freest from 

 disease. As this is a soil fungus, rotation of crops should be urged, and the proba- 

 bility of resistant varieties is mentioned. 



Brief notes are given on the bacterial disease of potatoes and the relation between 

 leaf-eating insects and this bacterial blight is pointed out. 



Potato failures, F. M. Rolfs (Colorado Sla. Bui. 91, pp. 33, pis. 5). — This is a 

 second report of the author's investigations on the so-called Rhizoctonia disease of 

 potatoes. In a previous publication (E. S. R., 14, p. 159) the results of experiments 

 and studies of the Rhizoctonia of the potato for 1901 were given. This disease is 

 widely distributed throughout the United States and the fungus is of a truly para- 

 sitic nature. The different stages of the fungus are described, and from present 

 information it is attributed to the fungus Corticium vagum solani. The fruiting stage 

 of the fungus has been previously reported (E. S. It., 15, p. 686). 



The effect of the organism on the plaid orstalk, on the tubers, and the rotting of 

 the seed is described, and it is found that high temperatures and plenty of moisture 

 contribute very materially to the rate of growth. Heavy, poorly drained soils seem 



