BUREAU OF PLA^STT INDUSTRY. 279 



that part of the country will occur sooner than had been estimated. 

 Ihe Chinese chestnut (Castanea mollissima) has been found quite 

 resistant to the blight. 



The chestnut and white pines, two of our most important trees from 

 the standpoint of prohtable management of forest lands, have been 

 seriously attacked by imported fungi. One is being rapidly de- 

 stroyed, while in the other case the disease will be controlled only at 

 considerable expense and after very severe losses have occurred. 

 Another of our important trees, the Douglas fir, is threatened by a 

 serious canker which is prevalent on this tree in Scotland. This 

 canker also attacks larch and hemlock. It is entirely possible that 

 this disease is already in this country. The knowledge of forest dis- 

 eases in the eastern United States is so limited that the fungus could 

 easily have gained a considerable foothold without being reported. 



WOOD CONSERVATION. 



Study of the causes and control of decay in lumber and other wood 

 products is carried on in cooperation with the Forest Products Labo- 

 ratory of the Forest Service at Madison, Wis. The following are 

 examples of the differeiit lines of industiy which are interested and 

 actively cooperating in the work of the branch office: The paper 

 companies on the prevention of decay in both stored wood and pulp ; 

 the airplane industry on defects in propellers; the automobile and 

 furniture industries on hidden pathological defects in lumber, es- 

 pecially the interior dote of elm; and the various lumber associations 

 with their blue-stain problem. 



During the fiscal j-ear the decay of building timbers has been in- 

 vestigated in Kentucky, Tennessee, Missouri, Arkansas, Oklahoma, 

 Mississippi, Louisiana, and Alabama. The study in Alabama was 

 made at the request of the State commissioner of conservation and 

 in cooperation with him. Articles have been published in trade jour- 

 nals describing the most destructive building-rot fungus of the South 

 and outlining methods of control. 



Further experiments on the preservation of ground wood pulp 

 have been made toward improving the methods employed and re- 

 ducing the cost of preservative treatment. Laboratory tests indicate 

 that one of the new substances under trial may reduce the present 

 cost of preserving pulp from about $2.50 to approximately 50 cents 

 a ton. 



The problems involved in controlling or lessening blue-stain in 

 lumber have been studied, and a preliminary field survey has been 

 made in the southern yellow-pine region. Laboratory dipping ex- 

 periments have been started in a search for a treating solution which 

 will be effective in controlling the staining fungi. Wliile much 

 progress has been made, the waste due to this fungous trouble still 

 aggregates approximately $10,000,000 a year, and further intensive 

 investigation is urgently needed. 



PLANT NUTRITION. 



LENGTH-OF-DAY RESPONSE. 



Through continuing investigations on the effect of the length of 

 day on plant growth it has been found that there is an important 

 interrelationship between the length of day and the temperature level 



78007— AGR 1923 1 9 



