550 EXPERIMENT STATION EECOED. 



coiulilhin. At this time tlie spores of the fungus are very readily carried from 

 plaut to plant, the disease being spread in this manner, while when dry there 

 is little possibility of infection. 



New facts concerning warty disease of potato, J. Percival {Gard. Chron., 

 3. ser., 46 (1009), No. 1179, p. 19, fig. 1). — This disease, which is due to Chryso- 

 phlyctis cndoMotiva, was first described in 1896. It is often spoken of as 

 black scab, but the author thinks that warty disease would better describe it, as 

 the tubers are not usually blackened as the name would indicate. 



While examining tubers exhibiting this peculiar disease, the author was 

 able to carry on some experiments which clear up some of the facts regarding 

 the develoi)ment of the parasite. When' a cross section is made late in summer 

 or autumn of the warty excrescence on a diseased tuber, large brown, thick- 

 walled spores are seen embedded in the tissues beneath. Usually only one spore 

 is present in each infected cell, although sometimes cells contain two. The 

 diseased portion of the tuber, if left in the ground, becomes disorganized, and 

 the spores are set free in the soil. 



In the spring of the year the thick outer coat of the spore bursts and a 

 large number of zoospores are liberated. These make their way through the 

 soil by means of cilia, but this motion ceases in a short time and the zoospores 

 then become amoeboid and enter into the cells of any young potato plant with 

 which they may come in contact. The formation of zoosporangia and the 

 setting free of zoospores may be repeated indefinitely during the early summer, 

 but later resting cells are produced which carry the organism over to the 

 following spring. The parts of the potato attacked by the parasite are stimu- 

 lated, rapid division of the cells near the point of infestation occurs, and an 

 extraordinary proliferation of the tissues is effected, the new growth often 

 resembling a piece of cauliflower. 



Experiments on the combined treatment for Botry tis and Coniothyrium, 

 G. DE IsTVANFFi {Bill. Inst. Cent. Ampelol. Roy. Hongrois, 1 {1906), pp. 16, 11 

 [pul). 1908] ) . — Experiments were conducted to control by simultaneous appli- 

 cation of fungicides the two fungi mentioned above, the application being made 

 toward the end of July. Mixtures of sulphur and copper, of sulphur, bisul- 

 phite of soda, and copper acetate, of sulphur and bisulphite of soda, and of 

 lime and sulphur were used. The treatments were efficient in greatly reducing 

 the Botrytis, and almost entirely prevented the occurrence of the Coniothyrium. 



Contributions to the know^ledg'e of Dematophera, G. de Istvanffi {Bvl. 

 Inst. Cent. Am2)^Jol. Roy. Hongrois, 1 {1906), pp. 18-20 [pub. 1908]). ^A study 

 was made of D. glomerata and D. nccatrix, the first species being much more 

 common than the second. 



The presence of these fungi on grapevines is indicated by the leaves becom- 

 ing crumpled, drying along their borders as if burned. Later the entire leaf 

 becomes yellow and dries slowly, and sometimes new leaves are put out which 

 remain small and i*esemble those of the gooseberry. The fungi, which attack 

 the roots, develop in humid soils, particularly where there is poor aeration. 

 Too great abundance of fertilizers, particularly barnyard manure, also favors 

 the development of the parasites. Studies were made with the various spore 

 forms, and descriptions are given of the different stages in the development of 

 the fungi. 



Prevention of " pourridie," A. Szigethi-Gyula {Bui. Inst. Cent. Anip6lol. 

 Roy. Hongrois, 1 {1906), p. 16 [pub. 1908]). — Experiments in a vineyard located 

 in a rather moist situation showed that the application of lime at the rate of 

 2 kg., or of 10 liters of milk-of-lime, to a vine was efficient in preventing the 

 pourridie. 



