20 



MASS. EXPERIMENT STATION BULLETIN 305 



ing-off which occurred was caused by species of Pythium, although Rhizoctonia 

 was also present in some instances. 



Results of some of the experiments are tabulated below. The work to date is, 

 of course, only preliminary, and the results should be considered as indicative 

 rather than final. 



Material Tested 



Aluminum 

 sulfate 



Grams per 

 Square 

 Foot of 



Soil 

 Surface 



20 

 25 



30 



40 



Effect on 

 Damping-off 



Not controlled 

 Not controlled 



Not controlled 

 Less than check 



Effect on Plants 



Harmless to all species used. 



Some injury to foxglove {Digitalis piirpurea), 



aster (Callislephus chinensis), and beet. 

 Injurious to Primula polyantka and cucumber; 



harmless to Calendula officinalis, sweet pea, 



and lupine {Lupinus polypliyllus). 

 Somewhat toxic to all species used except 



Dianthus. 



Ammonium 

 hydroxide (1) 

 (sp. gr. 0.9) 



Ammonium 



sulfocyanate (1) 



fl:60* 

 l:oO* 

 ) 1 :40* 



1:30* 



Not controlled 

 Fair control 

 Good control 



Good control 



Not controlled 

 Not controlled 



Not controlled 



Harmless to all species used. 

 Harmless to all species used. 

 Some injury to Alyssuvi saxatile and sweet 



alyssum (Lobularia mariiima). 

 Toxic to Alyssum saxatile, sweet alyssum, sweet 

 pea, Scabiosa atropurpurea, beet and cucumber. 



Harmless to all species used. 



Harmless to sweet alyssum. Calendula, and 

 beet; slight injury to cucumber. 



Harmless to sweet pea and Calendula; injuri- 

 ous to cucumber and sweet alyssum. 



Calcium acetate 



Calcium 



cyanamide (1) 



Calcium 



hypochlorite (1) 



Copper, metallic 

 (a powder, 99.87o 

 metallic copper) 



Copper-lime dust 

 (85-15) 



Copper sulfate 



Mercuric chloride 



Potassium 



permanganate 



20 

 40 

 50 



1.5 

 2.0 



Not controlled 

 Not controlled 

 Less than check 



Good control 



Good control 



Not controlled 



Not controlled 

 Less than check 



Less than check 



Not controlled 



Not controlled 

 Less than check 



Not controlled 

 Not controlled 



2.25 Not controlled 



10 

 20 

 30 



Not controlled 

 Not controlled 

 Not controlled 



] Harmless or somewhat beneficial to Delphin- 

 > ium, hollyhock, mignonette, Salpiglossis, 

 j sweet pea, heliotrope, and petunia. 



Benefited Salpiglossis and Campanula medium; 



harmless to Calendula, sweet pea, and sweet 



alyssum. 

 Harmless to Alyssum rostralum, beet, and 



cucumber; toxic to Scabiosa. 



Toxic to Centaurea imperialis, sweet alyssum, 



and beet. 

 Harmless to sweet pea. 

 Toxic to sweet pea, Anchusa azurea, Lilium 



regale, and nasturtium {Tropaeolum majus). 

 Very toxic to foxglove and common heliotrope; 



slightly toxic to stocks {Matthiola incana 



var. annua). 



Toxic to sweet pea, Calendula, beet, and 



cucumber. 

 Toxic also to mignonette, foxglove, aster, and 



heliotrope. 

 Somewhat toxic to all species used. 



Injurious in some soils to sweet pea, beet, and 



cucumber. 

 Harmless to mignonette. 

 Toxic to Delphinium but not to hollyhock. 



Harmless to sweet pea and garden Verbena; 

 toxic to aster. Campanula medium, Viola 

 cornuta, and Calendula. 



Harmless to beet and cucumber; toxic to 

 mignonette. 



Toxic to sweet pea. Verbena, beet, and cucum- 

 ber. 



Toxic to Campanula medium and Arabis albida. 

 Harmless to sweet pea and Dianthus species; 



injurious to cucumber. 

 Harmless to sweet pea: toxic to Dianthus and 



lupine. 



Harmless to all species used (petunia, .Arabis, 

 aster, .Aubrieta, beet, and cucumber). 



