14 MASS. EXPERIMENT STATION BULLETIN 394 



Table 11. — Suggested Rates of Application of 



Formaldehyde Immediately After Seeding, for the 



Control of Damping-off of Vegetables 



Formaldehyde 

 Vegetable (In 0.8 Quart Water 



per Square Foot)* 



Beet 2.5 cc. 



Celery and celeriac 2.0 cc. 



Chicory 1 .75 cc. 



Cucumber 2.0 cc. 



Dandelion 1 .75 cc. 



Eggplant 2.5 cc. 



Endive 1.75 cc. 



Lettuce 1.75 cc. 



Muskmelon 2.0 cc. 



Onion 2.0 cc. 



Pepper 2.0 cc. 



Spinach 2.5 cc. 



Squash, summer 2.0 cc. 



Swiss chard 2.5 cc. 



Tomato 2.0 cc. 



*2.5 cc. formaldehyde thus applied = 1 fluid ounce in 2.5 gallons of 

 water on 12 square feet of seedbed; 2.0 cc. formaldehyde = 1 fluid ounce 

 in 3 gallons of water on 15 square feet; and 1.75 cc. formaldehyde 

 — 1 fluid ounce in 3.5 gallons of water on 17 square feet. 



Formaldehyde, properly diluted, may be applied to soil immediately after 

 sowing seeds of some vegetables without determining the exact rate of application 

 of the solution. Damping-off of a number of species was well and safely con- 

 trolled by 1 teaspoonful (4.9 cc.) formaldehyde in 1 gallon water (1 tablespoonful 

 in 3 gallons) when soil, after seeding, was watered with it without determining 

 the exact quantity of the solution applied per square foot (5). It is likely, how- 

 ever, to be 1.5 pints to 1.5 quarts of the solution, or about 0.9 to 1.8 cc. formalde- 

 hyde per square foot, and, at least with seme vegetables, the exact quantity of 

 water applied is not very important. As may be seen by reference to Table 12, 

 damping-off was well controlled by formaldehyde, 2 cc. per square foot, applied 

 immediately after seeding, whether 0.75, 1.25, or 1.75 quarts of the solution was 

 applied per square foot. The soil was moderately dry and there was some injury 

 to cress but not to cucumber, lettuce, and pea. 



Table 12. — Control of Damping-off by Formaldehyde, 2 cc. per Square 

 Foot, Applied in Different Quantities of Water 



Relative Number of Plants Percentages 



Treatment Which Lived Which Damped-ofT 



(Per Square Foot) Cress Cucumber Lettuce Pea Cress Cucumber Beet 



Check (water 1.25 quart) . . 100 100 100 100 31 31 14 

 Formaldehyde, 2 cc. 



In 0.75 quart water 123 



In 1.25 quart water 215 



In 1.75 quart water 174 



