60 EXPERIMENT STATIOX RECORD. 



Control of raisin insects, F. T. Bioletti {California Sta. Circ. iS-i (1915), 

 pp. 11, figs. 6). — ^A more detailed account of raisin insects and their control than 

 that previously noted (E. S. R., 32, p. 245). Descriptions and illustrations 

 are given of an insect trap for a refuse bos and of a gas-tight door for a fumigat- 

 ing room. 



Spraying scheme for the control of insect pests on citrus trees in Florida, 

 W. W. YoTHEES (Jour. Econ. Ent., S (1915), Xo. 2, pp. 161-164).— It is stated 

 that of the total damage caused by insects to citrus in Florida more than 95 

 per cent can be attributed to sis species, which in the order of their destructive- 

 ness are as follows : Citrus white fly, purple scale, rust mite, Florida red scale, 

 cloudy-winged white fly (Alcyrodcs nubifera), and the red spider (Tciranijchus 

 scxmaculatiis). The woolly white fly (A. hoicardi) and the purple mite (T. 

 mytilaspidis) are said to be of secondary importance. 



A spraying scheme which it is thought will largely eliminate the damage 

 caused by these pests, having been tested quite estensively for three seasons, 

 and generally with satisfactory results, consists in the application of paraffin 

 oil emulsion 1:50 in May; lime-sulphur solution 1:50 to 1:75, June to July; 

 paraflin oil emulsion 1 : 50, August 25 to October 31 ; and lime-sulphur solution 

 1 : 50 to 1 : 75. November or December. 



liiscellaneous insecticide investigations, E. W. Scott and E. H. Siegleb 

 (U. S. Dcpt. Agr. Bui. 218 (1915), pp. 47). — The autliors report upon" tests of 

 new and promising arsenicals and spray combinations made at Benton Harbor, 

 Mich., during the seasons 1912 (pp. 1-llK 1913 (pp. 11-19). and 1914 (pp. 

 19-27). 



The conclusions drawn as a result of the three seasons' work are as follows: 

 "Arsenate of lead proved to be the most consistent and valuable stomach poison 

 testedj giving satisfactory results throughout the esi>erimental work. Arsenate 

 of lead is equally effective in either the paste or powdered form. Triplumbic 

 arsenate of lead is less rapid as a poisoning agent than diplumbic arsenate, but 

 is .safer for use on tender foliage. Arsenate of lead may be combined with 

 nicotin solutions and lime-sulphur solution for the control of certain apple 

 chewing and sucking insects and fungus diseases. For the control of certain 

 sucking and chewing insects arsenate of lead may be combined with kerosene 

 emulsion. ^U'seuate of lead, kerosene emulsion, and lime-sulphur is an incom- 

 patible misture, due to the formation of an insoluble calcium soap and the 

 subsotiuent relea.<:e of free kerosene. In our esperience any combination con- 

 taining lime-sulphur and soap should not be useil, owing to the formation of 

 an insoluble calcium soap. Arsenate of lead should not be mised with sixlium 

 sulphid compounds, since the soluble soilium arsenate formeil is destructive to 

 leaf tissue. Arsenate of lead combined with a txtmmercial barium tetrasulphid 

 gave satisfactory control of the coiUing moth and caused no foliage injury in 

 the experimental apple orchard. 



The most promising new insecticide develoix^l during the course of the 

 esperimental work is arsenate of calcium. This arsenical may be manufactureil 

 at less cost than arsenate of load or .may be readily preparetl at home as de- 

 scribeil [in this bulletin]. During the seasons of 1912 and 1913 arsenate of 

 calcium gave encouraging results. In 1914 a commercial arsenate of calcium 

 paste in combination with lime-sulphur gave very satisfactory control of the 

 codling moth. While arsenate of calcium may have certain limitations, it will 

 doubtless prove of value for the control of chewing insects on certain ho.«t plants. 



"Arsenate of iron and arsenate of zinc are not as satisfactory as arsenate 

 of lead. Arsenite compounds are dangerous to use on tender foliage. In stnue 

 instances, however, it may be possible to prevent foliage injury somewhat by 

 combining the soluble arsenic with lime. Sodium-sulphur and potassiuiu-sul- 



