150 EXPERIMENT STATION KECOED. [Vol.36 



tannin, a content of 0.8 per cent or more caused a retardation of germination, 

 frequently followed by an abnormal stimulation of the growth of aerial 

 mycelium. The species of Endothia and to some extent the strains of the 

 same species showed considerable variations in their response to tannin. 

 In the course of the investigations it was found that tannin was utilized by 

 E. parasitica, the fungus being able to remove as much as 2 per cent from 

 the substratum. The specially prepared extracts of pure tannin were either 

 stimulating or only slightly toxic when combined with coloring matter or 

 other substances associated with tannins. 



The chestnut blig'ht and the white pine blight rust, A. B. Brooks (W. Va. 

 Dept. Agr. Bui. 12 {1915), pp. 21, figs. 9). — This bulletin gives a general account 

 of the chestnut disease due to Endotliia parasitica and a very brief discussion 

 of the blister rust of 5-leaved pines, the causal fungus of which has for its 

 alternate host currant or gooseberry. 



Eelworm parasites of plants, P. Frandsen {Mo. Bui. Com. Hort. Cal., 5 

 {1916), No. 2, pp. 60-63, fig. i).— This is an address made before the State 

 Fruit Growers' Convention, Palo Alto, Cal., 1915, giving the collected informa- 

 tion and results of recent experience regarding nematodes. Particular refer- 

 ence is made to Heterodcra radicicola, which is increasing in importance in 

 the Western States, about 500 species of plants, including the majority of 

 truck garden crops, alfalfa, clovers, some grains, a number of fruit trees, 

 and many weeds, now being known to be susceptible to this parasite. 



The young nematodes, as a rule, enter through the tip of the rootlet, but 

 they also pass into the young potato tubers through the lenticels, several enter- 

 ing frequently at the same point. They are distributed by such means as 

 seed potatoes and transplanted seedlings, irrigation being one of the most 

 important agencies. Soil thoroughly dried on tools or carried befoi'e the wind 

 apparently does not convey infection. Eggs and larvae are apparently com- 

 pletely destroyed in the stomach of animals fed upon infected plants. They 

 resist freezing temperatures for a limited time only, the long, cold winters of 

 the Northern States keeping them down in these localities. Character and 

 consistency of soil are thought to play a part also in frost resistance. At least 

 three months' time will be required to eradicate eelworms by flooding with 

 water, but drying for a few minutes will kill eggs or larvre, either on glass 

 slides or on roots and tubers. There is also very little resistance to heat. In 

 23 hours, infested potatoes were free from live parasites, yet unimpaired as 

 to germinability. It is thought probable that seed potatoes are safe after 24 

 hours' exposure to a temperature of 40° C. (104° F.). One per cent copper 

 sulphate, acting for two days on the nematodes, had no effect. Formalin is 

 also ineffective. 



Remedies suggested include the use of uninfested soil and seed, summer 

 fallowing of infested ground, deep plowing with consequent exposure of the 

 soil to the sun's rays in hot, dry weather, and a system of rotation employing 

 nonsusceptible crops, a number of which are mentioned. A marked infection 

 is said to have been obtained in an exiieriment with corn and oats, which have 

 been previously considered as immune. 



Injuries to plants kept in rooms, P. Sorauer {Ztschr. Pftanzenkrank., 25 

 {1915), No. 6, pp. S25-335). — Observations on several house plants as detailed 

 are considered to show that though injury from burning gas is theoretically 

 possible, this cause is practically inoperative and is easily avoided entirely by 

 ventilation. The injury which may be observed in case of several plants is 

 probably due to the elevation of temperature and the drying of the atmosphere 

 by the means employed to warm the air of the room. 



