DISEASES OF PLANTS. 863 



author states that 4 applications are all that are usually necessary, and 

 these should he given the vines at times which coincide with certain 

 easily distinguished periods of growth, namely, (1) when the young 

 shoots are 15 to 20 cm. in length; (2) at the time when the (lowers are 

 beginning to open; (3) at the close of the flowering period, and (4) 

 when the grapes have attained about one-half their full size. The most 

 critical time in combating the black rot is stated to be the fortnight 

 following flowering and the last half of July. 



In conclusion, the author states that the 4 applications given as above 

 will usually be found all that are necessary, but occasionally supple- 

 mental treatment will be necessary if a sudden attack of the fungus 

 should be imminent. 



The life history and characteristics of the pear-blight germ, 

 M. I>. Waite (Proc. Amer. Assoc. Adv. Sci., 47 (1898), pp. 127, 428). — 

 The author states that the first appearance of the germs on the new 

 growth of the season in the spring appears on the nectar disks. The 

 bacilli live and multiply in the nectar and are able to infest the host 

 without puncture or injury through the nectar glands. The distribu- 

 tion from flower to flower and tree to tree is through the agency of 

 insects. Infection also occurs on young shoots and less frequently on 

 the fleshy bark through injuries. No evidence has been found that 

 the germs are carried by the wind. The blight germs usually die out 

 in the twigs which are blighted, but in certain cases they manage to 

 keep alive through the summer, making slow growth in the fleshy 

 bark. Such cases may succeed in living over a winter, winter weather 

 being favorable to the longevity on account of moisture and low tem- 

 perature. These hold-over cases of blight are apparent in the spring 

 by the exudation of considerable quantities of gummy matter full of 

 bacilli. These are visited by insects, principally flies and wasps, which 

 carry the germs to the newly opened flowers, thus completing the life 

 cycle. 



The characters of the bacillus are briefly given, its appearance when 

 cultivated upon various media described, and certain statements for- 

 merly made which are now known to be erroneous are corrected. The 

 color of the germ mass, which has previously been stated to be yellowish 

 white on the potato, must have come, in the author's opinion, from 

 impure cultures as the true pear-blight germ is always white. No gas 

 is formed, contrary to previous expressions, and while the germ pro- 

 daces some acids, no butyric acid is produced in its decomposition. It 

 has been stated that starch is decomposed and used as food by the 

 germ in cultures, but in the author's experiments this has never been 

 demonstrated. It has also been claimed that the germ lives over 

 winter in the soil, but so far the author has failed to find any evidence 

 of this fact. 



Notes on some diseases of southern pines, H. von Schrenk 

 (Proc. Amer. Assoc. Adv. Set., 47 (1898), p. 414).— Of the numerous para- 

 sitic fungi attacking the species of southern pines, Trametes pini is said 



