ANNUAL REPORT, 1933 21 



Effect on Plants 



Harmless to sweet pea; toxic to beet and 

 cucumber. 



Harmless to Dianthus and Salpiglossis; some 

 injury to sweet pea and Campanula medium. 



Some toxicity to Bellis perennis and Salpi- 

 glossis; no injury to Dianthus species. 



Toxic to heliotrope, aster, Physostegia virgin- 



iana, and Bellis. 

 Not injurious to foxglove. 

 Toxic to foxglove. 



(1) Applied to soil 2 weeks before seeding. 



* Applied in water at the rate of 2 quarts of each dilution per square foot. 



Carnation Blight. (E. F. Guba, Waltham.) Additional varieties of carna- 

 tions that were studied and classified for susceptibility to blight caused by the 

 fungus Alternaria dianthi S. & H. are the following: 



Very Susceptible Slightly Susceptible Resistant 



Denver Luminosa Ocean Spray 



Minna Brenner Mary E. ^im My Love 



Wardelia Patrician Satellite 



Variegated Ward Scarlet Monarch Woburn 



Butterfly Golden Wonder 



Infestation of flatted plants with red spider mite contributed to an early 

 epidemic infection of blight in the field as compared with a natural belated 

 infection in the absence of mite. Further tests with potassium permanganate 

 solution as a disinfectant for cuttings before "sanding" substantiated the pre- 

 vious report of the merit of this treatment. No improvement in disinfection 

 was noted by the addition of a spreader to the solution. July benching gave 

 three times as many No. 1 carnations as August benching. Plants made from 

 December, January, February, and March cuttings showed no significant differ- 

 ences in disease control as indicated by yield. Plants housed in August and 

 treated in the field and benches with Bordeaux 4-4-50, containing J^ pint of 

 fish oil, gave twice as many No. 1 carnations as similar plants not treated. 



Monograph of the Genus Pestalotia. (E. F. Guba, Waltham.) The interest 

 manifest in this study has stimulated efforts to carry it further. During the past 

 year exsiccati collections from the Berlin Botanical Museum and from Dr. Charles 

 Fairman were examined, making possible much progress in the work. 



Forcing Gladiolus with the Aid of Artificial Light. (L. H. Jones.) Supple- 

 menting daylight with artificial light from 500-watt bulbs is a practical method 

 for securing blossoms of gladiolus, variety Crimson Glow. At least three weeks 

 of this light are necessary for the formation of flower spikes, and the greatest 

 number of spikes was obtained from plots that received ten or more weeks of 

 light at night. It was quite noticeable that the earliest blooms were obtained 

 from the plots that received light less than ten weeks. This bears out the results 

 of previous experiments which show that a little light shortened the period re- 

 quired for blossoming, while prolonged exposure to light lengthened the period. 



Plant Containers. (L. H. Jones.) Plant containers of copper and brass, with 

 and without drainage holes, have been tested. A variety of house plants, both 



