Nov. 15,1925 
Crown-gall Studies of Resistant Stocks for Prunus 
971 
Amygdalus mira , the smooth-pit peach of China, has shown a very 
satisfactory resistance. Seedlings of this species are now being 
tested. Amygdalus tangutica and A* persica potanini are promising. 
Seedling peaches from commercial pits and standard commercial 
varieties are much more susceptible. 
The Italian prune and other varieties of P. domestica (Table II) 
have shown resistance, and seedlings of these should be grown to 
test the inheritance of resistance. 
Prunus armeniaca (S. P. I. 32834) and P. armeniaca mandshurica 
seem to show a higher resistance than the commercial varieties of 
apricot or their seedlings that have thus far been tested. 
No practical method for using germicides in treating germinating 
pits or roots of the peach can as yet be recommended. 
LITERATURE CITED 
(1) Melhus, I. E., and Maney, T. J. 
1921. A STUDY OF THE CONTROL OF CROWN GALL ON APPLE GRAFTS IN THE 
nursery. Iowa Agr. Exp. Sta. Research Bui. 69: 159—172. 
(2) Riker, A. J. 
1923. SOME RELATIONS OF THE CROWNGALL ORGANISM TO ITS HOST TISSUE. 
Jour. Agr. Research 25: 119-132, illus. ' 
(3) Smith, C. O. 
1912. FURTHER PROOF OF THE CAUSE AND INFECTIOUSNESS OF CROWN GALL. 
Calif. Agr. Exp. Sta. Bui. 235: 531-557, illus. 
1916. PRELIMINARY STUDIES ON THE RESISTANCE OF PRUNUS TO ARTI¬ 
FICIAL inoculation with bacterium tumefaciens. Phyto¬ 
pathology 6: 186-194, illus. 
(5) - A 
1917. COMPARATIVE RESISTANCE OF PRUNUS TO CROWN GALL. Amer. 
Nat. 51: 47-60, illus. 
(6) Smith, E. F., Brown, N. A., and Townsend, C. O. tt . . 
1911. CROWN-GALL OF PLANTS: ITS CAUSE AND REMEDY. U. S. Dept. Agr., 
Bur. Plant. Indus. Bui. 213, 215 p., illus. 
(7) Toumey, J. W. 
1900. AN INQUIRY INTO THE PAUSE AND NATURE OF CROWN-GALL. AriZ. 
Agr. Exp. Sta. Bui. 33, 64 p., illus. 
