550 Journal of Agricultural Research voi. xv.no. lo 



Two pots of pine in autoclaved soil were heavily inoculated with agar 

 cultures of the species of Phoma which has been shown to cause the 

 blight of young cedar (lo). No damping-off resulted, although in the 

 same experiment both Corticium vagum and Pythium debaryanum proved 

 strongly parasitic. It has not been found in cultures from damped-off 

 seedlings. 



An unidentified species of Phoma from blighted 2 -year-old seedlings 

 of western yellow pine from Montana, used on five pots of jack pine in 

 experiment 31, apparently resulted in decreased rather than increased 

 damping-off. 



Inoculation with a bacillus which appeared commonly with Pythium 

 debaryanum from damped-off seedlings also appeared to decrease rather 

 than increase damping-off in experiment 31, and in the experiments on 

 soil treated with acid and lime to increase the loss, but in both cases to 

 an extent explainable as accidental variation. 



The statement made in several of the foregoing paragraphs that the 

 organisms considered apparently decreased damping-off in experiment 

 31 is not necessarily paradoxical, in view of the possibility of competi- 

 tion between saprophytic organisms and accidentally introduced parasites. 



It is realized that not all of the possible damping-off parasites have 

 been tested. In some cases it has proved very difficult to obtain from 

 damped-off seedlings any of the known parasitic organisms. It is de- 

 sirable to make further attempts to obtain, and to carry on inoculation 

 experiments with, slow-growing organisms not likely to appear in the 

 planted plate cultures used by the writers for isolation purposes. 



OTHER PARASITIC DISEASES 



Discosia pint Heald has been found on western yellow pine in the same 

 way as described by Heald (77) and at the same nursery. Obsei'vations 

 confirm his conclusion that it does little or no harm. Cultures were 

 obtained by making dilution plates of the spores, but the subcultures 

 were not carried long enough to obtain fruits. The same fungus was 

 found occurring in just the same way on white pine from a nursery in 

 Georgia. 



Another fungus occurring on living pine seedlings of the damping-off 

 age without causing the decay typical of damping-off is the European 

 rust Melampsora pinitorgua (A. de B.) Rostnip. This rather dangerous 

 parasite has not so far been reported authentically from America, and 

 its importation should be very carefully guarded against. It most com- 

 monly attacks the young needles and shoots of trees 10 to 30 years old, 

 but it may also produce its orange sori on seedlings which have just 

 appeared above the soil surface {11, 24). Hartig {11) has found it 

 attacking as many as two-thirds of the seedlings in a stand of Scotch 

 pine, producing spores on the cotyledons and hypocotyls when the seed- 

 lings were only 2 months old. Seedlings recovered whose cotyledons 



