154 EXPERIMENT STATION RECORD. LVol. 41 



The author also reports having demonstrated the presence of stomata on 

 the imderside of the leaves of pineapple plants. 



Pathological laboratory [notes] {Roy. Bot. Gard. Kew, Bui. Misc. Inform., 

 No. 1 {1918), pp. S9-42). — In this portion of the 1917 report it is stated that, 

 although American gooseberry mildew appeared to be absent and whiteheads in 

 wheat less destructive than during the previous year, much browning and 

 scorching of potato foliage was noted. Among the diseases most prevalent were 

 black currant rust {Cronartiiim ribicola), bean pod canker, potato blackleg and 

 scab, plum rust, die-back and sooty blotch of apples, and onion diseases 

 (Sclerotiuia and Botrytis). Notes are also given regarding American goose- 

 berry mildew {Sphwrotheca mors-uvce), parsnip canker, potato wart disease, 

 and apple mildew {Podosphcera leucotricha) . A comparative study has been 

 made of the morphology and parasitism of the fungus B. cinerea, particularly in 

 ^sculus pavia and Ribcs alpinum. Progress has also been made in the investi- 

 gation of Thidavia basicola. 



Pathological problems in the distribution of perishable plant products, 

 C. L. Shear {Brooklyn Bot. Gard. Mem., 1 {1918), pp. 415-422, pis. 3). — In order 

 to indicate the variety and complexity of the problems involved in the trans- 

 portation of perishable plant products, typical cases are described in connection 

 with suggestions regarding protective measures considered as practicable. 



Seed disinfection by formaldehyde vapor, C. C. Thomas {Jour. Agr. Research 

 [f/. -S'.], 11 {1919), No. 1, pp. 33-39, fiy. i).— In a contribution from the Federal 

 Horticultural Board, U. S. Department of Agriculture, a preliminary report is 

 given of a study of methods of seed disinfection that would be applicable to the 

 treatment of considerable quantities of seed. The author devised a form of 

 apparatus by which formaldehyde vapor may be used, and he reports upon the 

 effect on seeds as well as on fungi and bacteria of various strengths of the 

 vapor employed for different periods of time. 



A tabulation is given showing the effect of formaldehyde vapor on 20 dif- 

 ferent kinds of seeds, from which it appears that little or no injury followed 

 the subjection of the seed for from 1 to 3 hours to the formaldehyde vapor. 

 Studies of various fungi and bacteria showed that the formaldehyde solution 

 vapor destroyed the organisms in about 1 hour if they were exposed in a thin 

 film, but where masses of spores were used more time was required to kill 

 them. Formaldehyde vapor and a 2 per cent formalin solution were compared, 

 10 different kinds of seeds being used, and in all cases the 2 per cent formalin 

 solution sample was intermediate between the checks and those treated with 

 formaldehyde vapor. The vapor treated samples are said to have been remark- 

 ably free from fungi and bacteria. 



In conclusion, the author states that the use of liquids for disinfection is 

 unsatisfactory for many kinds of seeds. A number of species of fungi and 

 bacteria were kiUed when treated for 2 hours with 20 oz. formaldehyde 

 vaporized in 1,000 cu. ft. without any injury to the seeds tested. 



An epidemic of corn smut following hail, H. G. MacMillan {Phytopathol- 

 ogy, 8 {1918), No. 11, pp. 584, 585). — An account is given of an epidemic of corn 

 smut following a severe hailstorm in a small district near Greeley, Colo. Six- 

 teen days after the storm, fields of smutted corn were observed averaging 19 

 per cent of infection, while other fields outside the hail area showed only 1 

 per cent of infection. 



Varietal susceptibility of beans to strains of Colletotrichum lindemuthi- 

 anum, M. F. Barbus {Phytopathology. 8 {1918), No. 12, pp. 58D-61.'i. pis. 5).— 

 On account of the possible bearing on plant breeding and also as possibly offer- 

 ing some suggestions as to the factors responsible for resistance to disease, 



