169 



Leach, J. G-. 19^+0 Insect transmission of plant diseases 

 6l5 pp. McGraw-Hill Book Company, New York. 



Phytomon as melophthora Allen and Riker 

 Insect concerned: The apple maggot, Rhagoletis pomonella . 



This "bacterium is pathogenic for apples and is found 

 associated with the apple maggot, Rhagoletis pomonella . 



Allen and Riker (1932) studied the decay of apples 

 which frequently follows infestation "by the apple maggot. 

 They associated the decay with a "bacterium which they 

 named Phytomonas melophthora . Besides "being associated 

 with the larvae, this "bacterium has "been found hoth in and 

 on male and female flies. 



For a description of this organism see Bergey's Manual 

 (5th ed., page 199). 



*Allen, T. C. , and Riker, A. J. 1932 A rot of apple 

 fruit caused "by Phytomonas melophthora , n. sp. , follow- 

 ing invasion "by the apple maggot. Phytopath. , 22, 557~ 

 571. 



Phytomonas pseudotsugae (Hansen and Smith) 

 Insect concerned: Chermes cooleyi . 



Phytomonas pseudotsugae was isolated from galls on 

 Douglas fir ( Pseudotsuga taxifolia) in California. Hansen 

 and Smith (1937) designated the causative agent Bacterium 

 pseudotsugae , which has since "been placed in the genus 

 Phytomonas . The infection depends on deep wounds which 

 suggests transmission "by an insect vector. Strong circum- 

 stantial evidence incriminates Chermes cooleyi , a sucking 

 insect. 



See Bergey's Manual (5th ed. , page 209) fo r a descrip- 

 tion of this organism. 



^-Hansen, H. N. , and Smith, R. E. 1927 A hacterial gall 

 disease of Douglas fir, Pseudotsuga taxifolia . Hilgardia, 



10, 569-577. 



