374 PATHOLOGY [Bot. Absts. 



2555. Aubert, L.-G. L'oidium et les chenes de l'Ouest de la France. [Oldium and the 

 oaks of western France.] Rev. Eauxet Forets 57: 189-195. 1919. — See Bot. Absts. 3, Entry 

 1996. 



2556. Atjdbbert, O. La defense rationnelle de la vigne contre le mildiou. [Rational pro- 

 tection for grapevines against downy mildew.] Prog. Agric. et Vitic.69: 445 - 1 19. 1918. — A 

 definite plan for spraying the vineyard based on the development of new and unprotected 

 foliage. — D. Reddick. 



2557. Ball, E. D. The potato leafhopper and the hopperburn that it causes. Bienn. Rept. 

 Wisconsin Dept. Agric. 1917-18: 76-102. PI. 1-6. 1918. Also Wisconsin Dept. Agric. Bull. 

 23: 76-102. PL 1-6. 1919. — A part of the injury to potatoes usually known as tip burn is 

 caused by the leaf hopper, Empoasca mali. This type of tip burn, conveniently designated 

 as hopper burn, appears at first as ". . . . a triangular brown area at the tip of the leaf 

 running back on the midrib .... followed by a progressive burning of the margin, 

 usuallj r from the tip backward but occasionally in more or less triangular spots appearing 

 along the margin, each one of these centered in a lateral veinlet. These increase in area and 

 the burnt narrow strip along the midrib remains green and in serious cases this weakens and 

 dies and the leaf shrivels up." Adult parasites live through the winter, fly to the potato fields 

 early in June, lay eggs and disappear during the month of August. Nymphs of the second 

 generation appear during July, remain for the most part, on the particular leaf on which they 

 were hatched, and furnish the adults for hibernation. Effective control measures, so far as 

 worked out, consist of two applications of a contact insecticide applied in such a way as to 

 reach the insect on the under side of the leaf, the first application being made when the burn- 

 ing begins to appear, the second two weeks later. — Charles R. Stevenson. 



2558. Ball, E. D. Spuay material and application. Rept. Iowa State Hortic. Soc. 53: 

 76-85. 1918. — A brief discussion of spraying and spray material. — L. H. Parnmel. 



2559. Ball, E. D. What burned the potato leaves last summer? Rept. Iowa State Hor- 

 tic. Soc. 53: 335-336. 1918. — Ascribes the burning of potato leaves to a minute green leaf 

 hopper {Empoasci mali) which hereafter is to be known as the potato leaf hopper. — L. H, 

 Pommel. 



2560. Ball, E. D., and S. B. Fracker. White pine blister rust. Bienn. Rept. Wis- 

 consin Dept. Agric. 1917-18: 40-43. 1918. Also Wisconsin Dept. Agric. Bull. 23: 40-43. 

 1918. — Eradication of pine trees and species of Ribes affected with blister rust (Cronartium 

 ribicola) in a limited area was successful. — Scouting in 1918 revealed the disease in 10 counties 

 in which it had been hitherto unknown. — The infected area is too great to warrant further 

 attempts at complete eradication of the disease from the State. — D. Reddick. 



2561. Ball, E. D., and S. B. Fracker. The eradication of barberry in Wisconsin. Bienn. 

 Rept. Wisconsin Sept. Agric. 1917-18: 44-56. 1918. Also Wisconsin Dept. Agric. Bull. 23: 

 44-56. 1918. — An account of the work done in Wisconsin as a part of the national program to 

 eliminate aecial hosts of Puccinia graminis in the '"wheat belt." — 95,000 bushes are known to 

 have been destroyed but it is estimated that the work of volunteers would bring the number 

 up to 250,000/ — Barberry was brought into the State by the earliest settlers and has escaped 

 widely. Many interesting records were traced and are reported. — D. Reddick. 



2562. Barber, C. A. Reminiscences of sugar cane work in India. Internat. Sugar Jour. 

 21:390-395. 1919. 



2563. Barss, H. P. International potato disease conference. Potato Mag. 2 2 : 5-6, 27-30. 

 6 fig. 1919. — Chiefly concerns leaf roll, mosaic, spindling sprout, and methods of cooperation. 

 — Donald Folsom. 



2564. Bartlett, F. A. Tree surgery. Sci. Amer. Suppl. 87: 200-201. 5 fig. 1919. 



