2 BULLETIN 453, U. S. DEPARTMENT OP AGRICULTURE. 



visible at any one time is but a small part of the total loss. Fur- 

 thermore, many of the seedlings are killed immediately after the 

 seed sprouts and before the seedlings appear above the soil surface. 

 Many failures hitherto attributed to poor germination are in reality 

 due to the work of the damping-off parasites in the sprouting seed, 

 underground. The high price of most evergreen seed makes this loss 

 of young seedlings a serious matter. 



The cost of seed ] ranges from a minimum price of 50 cents per 

 pound for western yellow pine (Pinus ponder osa Laws.) collected by 

 the United States Forest Service to $2 to $4 per pound quoted by 

 commercial seedsmen for the native spruces and $5 to $10 per pound 

 for Norway pine (Pinus resinosa Ait.). The regular annual loss is, 

 however, not the most serious result of the disease. The most trouble- 

 some thing from the commercial standpoint is the great variation in 

 the prevalence of the disease. In some seasons the loss is relatively 

 slight, while in others the seed beds may be almost a total loss. The 

 results of a damping-off epidemic are shown by the poor stand in 

 the untreated plats in Plate I. Such epidemics make it impossible 

 for a nurseryman to secure any regularity in production. The diffi- 

 culty of controlling damping-off has caused many nurserymen to 

 give up raising their own seedling conifers. 



The loss from damping-off can not be figured merely on a basis of 

 the number of the seedlings destroyed. The most serious aspect of 

 the disease is the extent to which planting is discouraged by it. Re- 

 forestation of watersheds is one of the great needs of the present time. 

 When interest on the cost of a forest plantation is compounded for 

 the 80 or 100 years which must elapse between forest planting and 

 timber cutting, a very slight initial increase in the cost of planting 

 stock becomes a heavy charge against the ultimate timber value of 

 the plantation, on which the owner must depend for direct returns. 

 It is necessary in order to encourage forest planting to eliminate all 

 possible cost items in the establishment of plantations. Both the 

 average loss and the irregularity in production due to damping-off 

 are reflected in the prices of coniferous planting stock, so that the 

 disease must be controlled to give the maximum opportunity for 

 profitable reforestation. It has previously been possible to import 

 pine stock from Europe cheaply. This has resulted in the introduc- 

 tion of very dangerous insect and fungous pests. The importation of 

 all pines is now prohibited, and the danger of the further introduction 

 of parasites on imported stock of other conifers makes it necessary 

 that the domestic nursery industry be developed on an economic 

 scale that will eliminate all need or incentive for importation. To 

 do this, all important native diseases, of which damping-off is the 

 most serious, must be controlled. 



1 Information furnished by the Office of Forest Investigations, United States Forest Serviet. 



