No. 3, December, 1920] PATHOLOGY I So 



1268. Hamblin, C. O. Collar rot of citrus trees. Agric. Gaz. New South Wales 31: 439- 

 441. 6 Jig. 1920. — Description and treatment given for this disease which is caused by 

 Fusarium limonis Briosi. — L. R. Waldron. 



1269. Hartley, Carl. Stem lesions caused by excessive heat. Jour. Agric. Res. 14: 

 595-604. 1918. — "Whitespot" occurs on very young seedlings of conifers and certain other 

 plants and resembles closely typical "damping off." "The location of whitespot lesions on 

 the stems, their observed relation to insolation and to dry surface soil, and the production 

 of typical lesions by artificial heating, indicate excessive heat as the cause of most whitespot 

 trouble." Records show that surface soils may reach a temperature well over 50°C. — Lesions 

 on stems of similar plants ranging up to 4 years in age may be attributed to heat but further 

 experimental evidence is needed. — D. Reddick. 



1270. Harvey, R. B. Relation of catalase, oxidase, and H-concentration to the formation 

 of overgrowths. Amer. Jour. Bot. 7: 211-221. 2 fig. 1920.— See Bot. Absts. 6, Entry 1353. 



1271. Hoffer, G. N. Disease-free sweet corn seed. Purdue Univ. Agric. Exp. Sta. Bull. 

 233. 12 p., 8 fig. 1920. — This bulletin considers the experiments wherein sweet corn seed 

 was tested for infection by root- and stalk-rot pathogenes and then planted. Other experi- 

 ments dealt with ears selected by inspection as apparently sound. The symptoms of root 

 and stalk rots are briefly described and the effects of the rots on production are noted. Experi- 

 ments during 1919 at various places show a 10 to 30 per cent increase in yield from the appar- 

 ently disease-free seed ears over those which germinate well but are infected. The methods 

 of control recommended are (1) careful field selection and curing of the seed ears and (2) 

 testing the ears for seed infections on germinators. — G. N. Hoffer. 



1272. Htjngerford, Charles W. Rust in seed wheat and its relation to seedling infection. 

 Jour. Agric. Res. 19: 257-277. PI. 38~48, 1 fig. 1920. — Uredinia and telia of Puccinia gram- 

 inis tritici are found embedded in the pericarp on the hilar end of kernels of wheat (Triticum) 

 and sometimes along the ventral groove as far up as the middle of the kernel. Infected ker- 

 nels have black hilar ends and groups of telia appear as shining black specks under the lens. 

 The percentage of seed infection in the rust years, 1915 and 1916, was very low. A little over 

 1 per cent was the largest quantity found in any sample. Durum wheats are most commonly 

 affected. — The infection undoubtedly spreads to the kernel from original infection on rachis, 

 rachilla or glumes. — Germinating power of seed is not impaired by rust infection. Rust 

 infection in the field does not appear earlier on plants from infected seed than on plants from 

 clean seed. 2,500 plants from infected seed grown under controlled conditions developed no 

 rust. Mycelium was not found to spread from pericarp to young plants. Viable uredinio- 

 spores sown with seed failed to produce infection. — Stem rust is not transmitted from one 

 wheat crop to the next by means of infected seed. "In the writer's judgment, the occurrence 

 of stem rust sori in the pericarp of the caryopses of grains and grasses has no especial signifi- 

 cance; but the infection spreads to these tissues just as it does from an infection point in any 

 of the vegetative parts of the plant." — D. Reddick. 



1273. Htjtchtns, D. E. Insignis-pine disease. Jour. Agric. New Zealand 16: 37. 1918. 

 — An attack at Khandallah on insignis pine began in early winter and increased through the 

 wet season. It was worst in the warm wet spring. The leaves turned brown and dropped. 

 When dry weather set in new leaves pushed forth. This disease is distinct from the South 

 Australian disease caused by Peridermium. Climatic conditition are thought to be respons- 

 ible. — D. Reddick. 



1274. Jackson, A. B. A possible cause of spike in sandal. Indian Forester 45 : 635. 1919. 

 — A suggestion is made that spike might be caused by excessive parasitism of sandal on san- 

 dal. — E. N. Munns. 



1275. Jackson, H. S. New or noteworthy North American Ustilaginales. Mycologia 12: 

 149-156. 1920— See Bot. Absts. 6, Entry 775. 



