148 PATHOLOGY [Bot. Absts., Vol. IX, 



not exist. Aspergillus niger can invade the ear only during the milky stage and when it haa 

 been injured by the ear worm. Tests show that infected ears should not be used as seed 

 stock. — L. Pace. 



941. Thompstone, E., and A. M. Sawyer. Report on the work of the Botanical Section, 

 Northern Circle. Ann. Rept. Agric. Sta., Agric. Chem., Agric. Eng., Bot. Northern Circle, 

 and Asst. Entomol. Burma 1918-1919: 93-95. 1920. — Progress is reported in investigation of 

 a destructive sclerotial disease of Phaseolus lunatus [see Bot. Absts. 9, Entry 917] ; cotton breed- 

 ing; and other experimental work. — W infield Dudgeon. 



942. Walker, J. C. Onion smudge. Jour. Agric. Res. 20: 685-721. PL 80-85. 1921.— 

 Smudge occurs only on the scales and neck of the bulb of Alliu7n cepa. The causal organism 

 is Colletotrichum circinans (Berk.) Voglino, heretofore generally known as Vermicularia 

 circinans Berkeley. The fungus is pathogenic upon the scales of mature bulbs, but does not 

 attack actively growing parts of the plant with the exception of young seedlings, upon which 

 it sometimes produces "damping off." The fungus overwinters as stromata in infected scales. 

 Conidia are sensitive to desiccation except when remaining in waxy masses on the host; in 

 this latter condition a small percentage remain viable for a considerable period. Abundant 

 rainfall, together with a mean soil-temperature range between 20 and 30°C., favor the rapid 

 development of the disease in the field ; hot dry weather in midsummer checks its development. 

 Artificial drying of "sets" immediately following harvest also checks the disease but is not as 

 yet recommended as a general practice. — H. W. Dye. 



943. Walker, J. C. Rust of onion followed by a secondary parasite. Phytopathology 

 11: 87-90. Fig. 1-2. 1921. — A species of Botrytis has been found attacking the leaves and 

 seed stems of the top onion {Allium cepa var. bulbellifera) . It enters the host plant always 

 through lesions produced by a rust, apparently Puccinia asparagi. — The identity of the 

 Botrytis has not yet been determined. — B. B. Higgins. 



944. Weir, James R. Poljrporus dryadeus (Pers.) Fr. on conifers in the Northwest. 

 Phytopathology 11: 99. 1921. 



945. Zeller, S. M. A Cytospora canker of apple and another "die-back" fungus of 

 interest. [Abstract.] Phytopathology 11: 105. 1921. 



946. Zeller, S. M. A spur blight of pear caused by Botrytis. [Abstract.] Phytopathology 

 11: 105. 1921. 



947. Zeller, S. M. Heart-rot of prune and peach in Oregon. [Abstract.] Phytopath- 

 ology 11: 105. 1921. — In western Oregon the greater percentage of heart-rot in peach 

 {Arnygdalus persica) and prune {Prunus domestica) trees is due to Trametes carnea. Lenzites 

 sepiaria and Fames pinicola also cause some heart-rot in these trees. — B. B. Higgins. 



948. Zeller, S. M. Wood decay in orchard trees in Oregon. Oregon Agric. Exp. Sta. 

 Crop Pest and Hort. Rept. 3: 132-138. Fig. 35-37. 1921.— The organisms causing most 

 serious decay of cherry wood are Irpex lacteus, Polystictus versicolor, and P. hirsutus ; of apple 

 and pear wood P. versicolor; and of prune wood Trametes carnea, Lenzites sepiaria. Fames 

 pinicola, Stereum hirsutum, and others. Of trees having large pruning wounds a survey 

 showed 97 per cent to be decayed. Painting of the wounds with Bordeaux paste, and about 

 the edges with a mixture of asphalt and paraffin, is recommended. Copper nails or tacks 

 driven into the wound will supplement the antiseptic action of the Bordeaux paste. — E. J . 

 Kraus. 



ERADICATION AND CONTROL MEASURES 



949. Barss, H. p. Cylindrosporium leaf-spot of prune and cherry. Oregon. Agric. Exp. 

 Sta. Crop Pest and Hort. Rept. 3 : 15(3-158. Fig. 42-43. 1921.— Control is effected by spray- 



