ECONOMIC ZOOLOGY — ENTOMOLOGY. 49 



For controlling apple scab, 4 applications of a 1 : 40 lime-sulphur solution to 

 which 2 lbs. of lead arsenate has been added is advised. The first application 

 should come just before the blossoms open, the second after the blossoms fall, 

 the third two weeks later, and the fourth 9 weeks after the blossoms fall. For 

 pear scab, the number of applications will have to be increased in orchards 

 where the scab fungus has become well established on the twigs, as the fungus 

 in these infected twigs continues to grow throughout the season, constantly pro- 

 ducing a crop of spores for the continuous infection of leaves and fruit. 



Studies of the fungicidal value of lime-sulphur preparations, E. Wallace, 

 F. M. Blodgett, and L. R. Hesler (New York ComeU Sm. Bui. 290, pp. 167- 

 207, pi. 1, figs. 2).— A report is made on the results of experiments for testing 

 the fungicidal value of different strengths of lime-sulphur mixtures. 



The method of testing the fungicide was as follows : Glass slides were sprayed 

 with the material to be tested and subjected to atmospheric conditions until the 

 coating of spray had thoroughly dried; then drops of water containing viable 

 spores of the fungus were placed on the sprayed slides, and also as checks on 

 unsprayed slides. The number of spores which germinated on the slides was 

 used as a criterion of the germicidal power of the spray under consideration. 



Lime-sulphur solutions, at a strength safe for foliage, were found by both 

 field and laboratory tests to be only fairly effective as a fungicide. In general, 

 a stronger concentration was required to prevent germination of conidia of 

 scab {Venturia ino'qualis) than those of brown rot {Sclerotinia fructigena), 

 and still stronger for apple canker {^^phferopsis malorum). Arsenate of lead 

 used alone seemed to have s6me fungicidal value which showed up better in 

 the field than in the laboratory tests, probably due to its adhesive properties 

 which kept the surface of the host coated with the poison so that the fungus 

 hyphse could not penetrate the leaf. The addition of arsenate of lead to the 

 lime-sulphur material increased the fungicidal value of the mixture (see above). 

 The action of carbon dio'xid on the lime sulphur, although entirely changing its 

 chemical composition, did not materially affect its fungicidal value. The addi- 

 tion of lime or of iron sulphate to the lime-sulphur solution seemed to increase 

 its efficiency slightly. When arsenate of lead was added to the iron-sulphate 

 lime-sulphur mixture, the increase in efficiency observed when arsenic was 

 added to the lime-sulphur mixture did not occur. 



The spore itself seems to be active in bringing into solution small quantities 

 of the fungicide, which in turn prevents germination. 



The preparation of copper sprays, G. Chappaz (Prog. Agr. et Vit. (Ed. VEst- 

 Centre), 32 (1911), No. 10, pp. 2 89-29 Jf).— The author gives the formulas and 

 describes the methods of preparing the various copper sprays which are used in 

 combating fungus diseases of the orchard. 



ECONOMIC ZOOLOGY— ENTOMOLOGY. 



Seed-eating mammals in relation to reforestation, N. Dearborn (f7. 8. 

 Dept. Agr., Bur. Biol. Survey Circ. 78, pp. 5, figs. 3).— This circular reports the 

 results to date of investigations conducted by the Biological Survey in coopera- 

 tion with the Forest Service for the purpose of devising methods of protecting 

 seeds from destructive rodents. It is stated that the protection of newly 

 planted seeds from the attacks of mice, chipmunks, ground squirrels, and other 

 rodents, the depredations from which collectively continue the year through, 

 furnish one of the most serious problems connected with the reforestation of 

 treeless areas within the National Forests. 



In exhaustive trappings on a half acre containing 2,000 seed spots, 3 chip- 

 munks and 11 white-footed mice were secured which in the course of 3 days 



