DANGEROUS INTERNATIONAL FOREST TREE DISEASES 47 



Hosts : Scrophulariaceae — 

 Paulownia tomentosa, 

 P. fortunei, 

 P. kawakamii. 



Literature : 

 Tokushisre, Y. Witches' broom of Paulownia tomentosa, L. Jour. 



Fac. Agr., Kyushu Univ. 10 : 45-67. 1951. 

 Witches' broom of Paulownia tomentosa L. On the occur- 

 rence of the witches' broom affected trees in paulownia forest 

 (Japanese with English resume). Jour. Jap. Forest Soc. 34: 

 4-7. 1952. 



Bacterial Blight of Chestnut 



Pseudom-onas castaneae (Kawamura) Savulescu. The disease is 

 most conspicuous in buds and young shoots but also occurs on the 

 leaves, veins, petioles, and bracteal leaves, the last being usually at- 

 tacked first. The sign of the disease in the early stage is water-soaked 

 spots on the leaves and young shoots in which the cortical parenchyma 

 is destroyed, forming bacterial cavities and resulting in brown cracks. 

 Leaves attacked when young become distorted and leaves of infected 

 buds shrivel and die. White and yellow bacteria are isolated from 

 the diseased lesions, of which the former is pathogenic to chestnut and 

 found associated with the latter. 



A short rod, 1.0-1.8/x X 0.8-1 .2/x, motile, with one to five polar 

 flagellar singly or in pairs, no spores, no capsules, Gram-negative, 

 facultative anaerobic, beef agar colonies white, round, slightly undu- 

 late and viscid, bouillon clouds without pellicle ; potato decoction agar 

 colonies white, radiately rugose, gelatin not liquefied, diastatic action 

 absent, milk peptonized without coagulation, indol and hydrogen su i_ 

 phide not produced, nitrate and methylene blue reduced, acid from 

 dextrose, saccharose and glycerine without gas, neither acid nor gas 

 produced from lactose, no gas from maltose and potassium. 



The distribution of this bacterium is limited to the southern districts 

 of Japan. Intercontinental spread may be possible only by infected 

 living trees, though pollen dissemination is also possible. 

 Range : Japan-Kyushu and Chugoku Districts. 

 Host : Fagaceae — Castanea crenata, 



C. mottissima. 

 Literature: Kawamura, E. Bacterial blight of chestnut (Japanese 

 with English resume) . Ann. Phytopath. Soc. Jap. 3 : 15-21. 1934. 



Needle Cast of Larch 



Mycosphaerella larici-I-eptohpis K. Ito & K. Sato. The earliest indi- 

 cation of the disease usually occurs during the first week in July. 

 Generally, scattered spots on the needle are first infected. They are at 

 first minute, brown, and surrounded by a faint yellow halo. As the 

 disease progresses, these spots increase in size and coalesce to attain a 

 width of 1 mm. or more. Lesions are present 5 to 7, rarely 20 per 

 needle. The discolored needles bear small black fruit spermogonia on 

 the upper surface of the dead area. From a distance the infected trees 

 give the appearance of having been scorched by fire or injured by late 

 frost. 



