Pecan Diseases, and Spraying Outfits 193 



ous by the failure of infected anthers to dehisce."^ The 

 diseased anthers contained degenerate or empty pollen-grains 

 which were often coUajpsed shells. 



The fungus, which was determined as a robust variety of 

 Microstroma juglandis, sometimes infects and destroys as 

 much as one-third of the pollen. However, since the pecan 

 normally produces a superabundance of pollen, the disease is 

 not likely to become a menace to the industry unless the in- 

 fectiousness of the organism becomes very much greater than 

 has thus far been reported. No measures of control have yet 

 been thought necessary, nor have any been offered. 



CROWN-GALL 



{Bactermm tuniefaciens, Sm. and Town.) 

 The well-known crown-gall organism which afflicts so many 

 orchard trees attacks the pecan also. While both the hard and 

 the soft types of crown-gall have been found on the pecan, 

 natural infection of either type is only occasional in the 

 nursery. The common practice of digging out and burning 

 all diseased plants recommended for nurseries in general is 

 equally applicable to the pecan nursery or infected trees. 

 "When a piece of soil is know^n to be badly infected with 

 crown-gall, pecans should not be planted there for several 

 years. 



PECAX BLACK-PIT 



This disease usually appears about midsummer, and in 



the early stages no evidence of infection or injury of any 



kind can be observed on the outside of the nut, but wathin 



there is a brow^ning and disorganization of the internal 



^Higgins. B. B. A Disease of Pecan Catkins, Phytopathology, 7: 

 pp. 42-45, Fig. 1, 1917. 



