DISEASES OK I'LANTS. 147 



rapid root (levelopiiii'iit, ami hy injecting thi- stt'rili/.cd juice of (li^oant'il piantH into 

 a growing bnd or pouring it upon the roots of a sound plant. The same disease has 

 ))een pnxhiceil l)y the author on tomatoes, jHjtatoi's, )tetunia,s, phytolaeca, vii>lels, and 

 otlier plants. The disease seems to be (iue to a disturbance in the balance between 

 the oxidizing enzyms and the availability of reserve foods of the i)lant. Tlie intro- 

 duction of the enzym pre.sent in the sterilized juice sets up a series of i)athological 

 changes in which the normal enzym of the cell is greatly increa.sed and the availa- 

 bility of the reserve foods decreased. It is believed that the diseases known as i)each 

 yellows and the California vine disease are to be similarly ex])lained, and diel)ack 

 of the orange may also be due to this cause. 



Spraying- for asparagus rust, F. A. Sikkine {Neu^ )'()rk- State >Sta. Bid. 188, pp. 

 ' 233-270, pJfi. IJ). — Notes are given on the liistory and distribution of the asparagus 

 rust {Piiccinid (tspdixufi) , together with descriptions of the various stages of its life 

 history. The various reconnnendations that luive been given for the control (jf this 

 disease are reviewed at some length. Burning the infested brush, which has 1)een 

 recommended by a number of writers, is said to be in some cases tletrimental, espe- 

 cially if the brush is cut and burned early in the season. This tends to weaken the 

 plants, and if continued would greatly depreciate the crop. The value of resistant 

 varieties is considered, and while some varieties seem less subject than others, there 

 is as yet ai)parently no variety which is not lial)le to attack. Soil conditions, as des- 

 cribed in Massachusetts Hatch Station Bulletin 61 (E. S. R., 11, p. 159), are reviewed, 

 and the author believes that fcjgs and dews prol)ably play an important part in the 

 spread of the disease, at least in the region covered by his investigations. Spraying 

 for the prevention of the disease has been reconnnended by some writers, and the 

 author conducted a series of experiments in whic'h plants were sprayed with Bor- 

 deaux mixture containing resin, 3 applications being given. This fungicide was 

 prepared by adding to a 1:8 formula of Bordeaux mixture a resin mixture com- 

 posed of 5 lbs. resin, 1 lb. potash lye, 1 lb. fish oil, and 5 gal. of water. This was 

 thoroughly si)rayed over the plants in August and Septendjer, and the effect upon 

 the subsequent crop noteil. The yield of Inmches in 1899 was increased 69.5 per 

 cent in the sprayed over the unsprayed plants, and in 1900 a gain of 48 per cent was 

 reported. This fungicide adheres quite readily, and with a thorough aijplication will 

 doubtless i)rove valualjle in combating this disease. The parasitic fungus Darlnca 

 liluin was noticed abundantly, but it has never been observed attacking the winter 

 spores of the rust, and there appear to be indications that this parasite will not 

 materially check the disease where asparagus is grown in large quantities. 



A form of power sprayer especially devised for spraying asparagus is described at 

 considerable length. The ajjparatus is not patented, and it is described in sutticient 

 detail so that any one desiring can manufai-ture a similar implement. 



Protecting asparagus, F. H. Hali, and F. A. Sikkine [Xeir York Stulf >Sla. Jiuls. 

 J88 fiii'l ]8!i, popiihir Cfl., pp. 14, figs. 5). — This is a popular summary of bulletins 188 

 and 1SV», giving directions for spraying for the jjrevention of fungus and insect pests. 



An investigation on damping off of seedlings, \'. Peglion {Stuz. Sper. Agr. 

 Jtal., 33 {1900), No. 3, pp. 221-337). — The fungi usually believed to cause tlamping 

 off are Phytophthora omnivora and Pythium debaryaiium. In addition to these, the 

 author finds that a number of other fungi attack seedlings in the same manner. 

 Among them are mentioned Botrytis clnfrca, Tklelavia hcmcola and Phovia hellcola. 

 The action of these different fungi upon the plant is described, and experiments for 

 preventing their attacks are outlined. The author conducted a series of experi- 

 ments in disinfecting soils by means of heating and by application of carbon bi.sul- 

 phid and formalin. Soil that was known to l)e infested witli Pythhun dchnryanuin 

 was heated to 60 and 100° C. and was treated with various amounts of carbon bisul- 

 phid and 20 and 80 jjer cent solutions of formalin. The soil was aftt-rwards seeded 

 to Camelina, which is known to be very susceptible to attacks of this fungus. lu 



