623 



QuAYLE (H. J.). The Citricola Scale. — California Univ. Agric. ColL 

 Expt. Sta., Berkeley, Bull. no. 255, May 1915, 17 pp., 7 figs., 

 [Received 10th August 1915.] 



The bulk of this paper has already been abstracted [see this Review, 

 Ser. A. iii, p. 457]. Against Coccus citricola, where fumigation is not 

 feasible, spraying may be employed. The kerosene emulsion spray 

 has proved the safest as regards injury to the tree or fruit, whilst being 

 effective in killing the scales. The kerosene spray is a mechanical 

 mixture of kerosene and water. The oil is used at a strength of from 

 8 to 10 per cent, and is mixed mechanically with water by agitation 

 in the spray tank. The oil used has the trade name of " Water white "' 

 or " W.W." and is a cheap kind of kerosene with a gravity of 42° Be. 

 Bv adding soap, an emulsion is obtained which the author considers 

 superior: "W.W." oil of 42°, 15 U.S. gals.; liquid soap, ^ gal. 

 (or hard soap 4 lb.) ; water, 200 gals. The materials are mixed in 

 the same way as for the following distillate emulsion : tree distillate 

 of 3r-32°, 4 U.S. gals. ; liquid soap, | gal. (or hard soap, 4 lb.) ; 

 water, 200 gals. To prepare this spray, first place the soap (hard soap- 

 must first be dissolved in hot water) in the spray tank with 10 or 15- 

 gals, of water. The engine is started and the emulsion is made by the 

 materials being run through the pump under pressure. After a few- 

 moments, the rest of the water may be added, with the pump still 

 working. TJie spray is then ready for use, and should be directed 

 almost entirely against the underside of the leaves. Two angle- 

 nozzles on a Y at the end of each rod is the best arrangement. 

 They should not throw too course a spray, otherwise too much material 

 will be used if any attempt at thoroughness in covering all parts of 

 the tree is to be made. Two applications are necessary ; usually 

 the first of these should be made in August or September, and the- 

 second a few weeks later. 



Prizer (J. A.). Nursery Fumigation. — MtJily. Bull. State Comyn.. 

 Hortic, Sacramento, iv, no. 7, July 1915, pp. 303-305, 1 fig. 



For dealing with a black-scale infestation in a citrus nursery, 44-foot 

 tents were used on sectional frames made to support one of these tents 

 and so constructed as to permit of easy movement through the 

 nursery. The cost of each frame was about I65. Two men could handle 

 3 tents in an hour and do the work carefully, the cost of labour per 

 hour being about 3^. A 16-ounce dose was used in each tent, so that 

 the cost of material per three tents was 35. 9d. The total cost per 

 three tents for one hour was therefore 6s. 9d. and as 420 trees were 

 covered, at the rate of 140 per tent, the cost per tree is less than a 

 farthing. Ten thousand trees were treated in spring and the results 

 were entirely satisfactory. An increased dose would have caused, 

 serious scorching in the locality where the work was performed, but 

 even if two fumigations were needed, as might be the case with red 

 or purple scale, the cost would not be prohibitive. 



Hall (H. V. M.). Another Fortunate Find.— Mthhj. Bull. State Comm.. 

 Hortic, Sacramento, iv, no. 7, July 1915, pp. 314-315. 



In May 1915, the author found among parcels in the post brought 

 for inspection, a package from Mexico containing a quantity of guavas. 



