DANGEROUS INTERNATIONAL FOREST TREE DISEASES 53 



The affected area becomes blackened and slightly depressed. As 

 the tissue dries, it turns dark brown. Stems less than 10 mm. in 

 diameter may be girdled by the fungus in one growing season. 



Dark greenish fruit-bodies of the causal fungus are produced 

 abundantly on the diseased needles and cankers of seedlings. As 

 cankers increase in size, the cambial tissue may be killed inward, 

 producing a flat-faced canker, swollen at the sides, and distorting 

 the stem. These cankers usually are perennial and increase longi- 

 tudinally for many years. Frequently the rapid growth of the stem 

 tissue prevents the girdling of the stem, and trees may live for many 

 years with one or more disfiguring but non-girdling cankers. 



Stromata dark brown, semi-spherical, fascicles dense, conidiophores 

 light yellowish-brown, rarely septate, non-branched, 4-6 X 40-80/*, 

 conidia pale yellowish-olivaceous, obclavate to obclavate-cylindric, 

 straight or slightly curved, echinulate, 3 to 7 septate, 5-9 X 30-85/*. 



This is the most important disease of conifers in Japan. Seedlings 

 and young trees are very susceptible. Infected seedlings are killed 

 by blighting and canker. Losses are very heavy, up to 90 percent 

 mortality in many nurseries. Intercontinental spread is possible 

 through shipment of infected trees or cuttings. The causal fungus is 

 very similar to Cercospora sequoiae Ellis & Ev. described on Sequoia 

 gigantea in the United States of America, Spraying with fungicides 

 in the nursery is very effective for control of the disease. 



Distribution : Japan, Formosa. 

 Hosts: Taxodiaceae — 



Cryptomeria jap cmica 



Sequoia gigantea (Planted in Japan) 



Literature : 



Ito, K. The cause of canker of Cryptomeria japonica (Japanese). 

 Plant Protect. (Tokyo) 6: 176-179. 1953. 



, Shibukawa, K., and Kobayashi, T. Etiological and patho- 

 logical studies on the needle blight of Cryptomeria japonica I. 

 Morphology and pathogenicity of the fungi inhabiting the blight- 

 ed needles. (Japanese with English resume.) Bui. Govt. Forest 

 Expt. Sta. 52 : 79-152. 1952. 



-, Shibukawa, K., and Kobayashi, T. Blight of Sequoia gi- 



gantea seedlings caused by Cercospora crvptomeriae Shirai 

 (Japanese). Jour. Jap. Forest Soc. 40: 407-410. 1958. 



Needle Blight of Pine 



Cercospora pini-densi florae Hori & Xambu. Yellowish-brown to 

 gray lesions appear mostly on the upper half of the needle as the 

 disease progresses, especially on 1- to 3-year-old trees. The needles 

 die to such an extent that it is known as "leaf -blight." 



Dark brown stromata fill the stomatal openings or as large as 60/* 

 in diameter, fascicles dense to very dense ; conidiophores dark brown, 

 rarely septate, not branched, sparingly geniculate, 2.5-5 X 10-45/j : 

 conidia pale yellowish olivaceous, obclavate to obclavate-cylindric, 

 straight to curved, 3-7 septate, rounded to obconicallv truncate base, 

 obtuse tip, 3-6 X 20-60/*. 



This is the most serious disease of pine seedlings. Heavily infected 

 seedlings die. Losses are heavy, up to 80 percent mortality in some 

 nurseries. 



