354 EXPEEIMENT STATION RECORD. 



caJeiuiii oxid, all tlioso limes produced washes of similar composition. In ex- 

 periments in adding varying proportions of sulphur to the lime, it was found 

 that it takes longer for the maximum amount of sulphur to go into combination 

 where the higher proportion is used. In experiments made to determine the 

 time necessary for complete combination, 3 brands of lime were used at the rate 

 of 20 lbs. to 15 lbs. of sulphur. With 2 brands the lime combination was prac- 

 tically effected at the end of 40 minutes, while with the third brand 1 hour was 

 required. It was found that direct heat induces a more rapid combination of 

 the lime and sulphur than does steam heat, but gives a wash of slightly lower 



value. 



I'lour of sulphur was found to combine somewhat more rapidly and slightly 

 more completely with the lime than does flowers of sulphur and has less tend- 

 ency to form the less valuable thiosulphate and sulphite. The wash was found 

 to become less valuable when allowed to cool before being applied. The de- 

 velopment of a green color in the wash during boiling was found to be due 

 largely to the presence of iron in the lime or to that derived from the vessel in 

 which the l>oiling was carried on. The length of time it takes for the color to 

 develo)) doi)ends upon the amount of iron or similar metal which is present. 



Fumigation with cyanid of potassium, II. L. Hutt and W. Hunt {Ann. 

 Rpt. Ontario Af/r. Vol. and Expt. Farm. 3', ( IHOS), pp. JUl, /6*,3).— Experiments 

 in continuation of previous work (E. S. R., 19, p. IIGO) with hydrocyanic-acid 

 gas for exterminating the greenhouse white fiy {Alcyrodv.'^ vaporariorum) 

 showed that a comparatively tight house is necessary for effective worlv. In 

 fumigating the black aphis on chrysanthemum the best results were obtained 

 by placing a jar or vessel of the material at least every 20 ft. throughout the 

 length of the house. The density of the foliage of these plants and the greater 

 vitality of the black aphis as compared with the white tly are factors necessi- 

 tating stronger fumigation. 



rumination investigations in California, 11. S. Woglum ( U. 8. Dcpt. Agr., 

 Bur. Ent. Bid. I'd, pp. 13, figs. 2S). — Tliis is a r('i)ort of fumigation investigations 

 which were commenced July, 1907, in California with the view of thoroughly 

 standardizing the process. 



The author first considers the insect enemies of citrus fruits and their dis- 

 tribution in California. The scale insects which are generally so d(>structive 

 as to require extended efforts for their control are the j)urple scale, the red 

 scale (CJrri/soniphaJus mirantii), and the black scale. Brief notes are included 

 on other less destructive species. " The most important i)ests other than scale 

 insects are to be found among the mites, of which the rust mite of the orange 

 or silver mite of the lemon (PhyUocoptm olch-orus) and the citrus red spider 

 (TetranycJitis mytilaspidis) are highly injurious. The orange aphis (Aphis 

 (jossijpii) becomes very numerous during some seasons but is soon attacked by 

 its natural enemies and held in control. A species of thrips [I*^- S. II., 20, p. 

 950], worked quite extensively in some localities on ripe oranges during the first 

 months of 1908, removing the coloring matter from beneath the epidermis, thus 

 giving to the fruit a spotted appearance wliich lowered its market grade." 



Trees have been noticed from 2 to 3 years after i^lanting which Iiave been 

 killed by the red scale. Large orchard trees are frequently destroyed by this 

 pest, while it is a common sight in regions of severe infestation to see large 

 branches killed back to the trunk. Although no trees have ever come to the 

 author's attention which were killed by the purple scale, severe infestations 

 are said to result in the destruction of many branches and to cause such a 

 drain on the tree that the production of fruit is greatly reduced. The purple 

 scale spreads to the fruit as does also the red scale, resulting in expense for 



