Proceedings, 1920. 105 



Control of Clothes-moth — Sulphur fumigation destroys adults and 

 larvae, not eggs. Heat at 110° Fahr. for 30 minutes kills all stages. Larvse 

 and eggs killed by dipping for 10 seconds in water at 140° F. Camphor and 

 naphthaline are the only materials fit to use in closets, etc. 



Control of Cockroaches. — Sodium fluoride has given best results. 

 Borax is good, but its action is slow. 



Red-spider Control. — Use soft-soap solution, 4 per cent, if buds are 

 closed ; soft soap i per cent, and nicotine 3 per cent. ; soft soap i per cent, 

 and quassia 2 per cent. A new spray where red spider is really bad has been 

 devised in California, uniting lime-sulphur, miscible oil, glue, and water. 



Sprays — Arsenate of Lead Spreaders. — Sage-brush tea, i lb. to i gallon; 

 allow to stand for 12 hours, 5-1,000. Casein lime: 3I/2 grammes quicklime 

 and i^ grammes casein; grind in mortar; 4-8 oz. to 100 gallons. 



Calcium Arsenate is not safe for general recommendation. It is sug- 

 gested for apples, potatoes, pear, but not for plum, cherry, or peach. Used 

 alone, it burns. One to ten of lime is safe for apple. Excess of lime pre- 

 vents arsenic going into solution. 



Dusting is rapidly replacing liquid sprays for many insect and disease 

 controls. The machinery and dusting mixtures have not as yet reached a 

 stage of perfection. To-day, relative cost is higher. They are using 80 to 

 85 per cent, sulphur, 10 to 15 per cent, powdered arsenate of lead, with 10 

 per cent, diluent, at 3 lb. per medium tree. Cherries may be dusted with- 

 out arsenate within a few days of picking. Dusting is cheaper for large 

 trees, 50 per cent, dearer for medium trees, and much more expensive for 

 small trees. Liquids hold better to leaves. Diluents or carriers are silt, 

 gypsum, talc, limestone. In general, liquid sprays are advocated until 

 dusting equipment is improved. 



Lime-sulphur is liable to cause injury with trees in poor vitality, appli- 

 cations in unusual heat, direction of spray with high humidity and high 

 sunshine record. 



Nicotine has been shown by several investigators to be an eflfective ovi- 

 cide, in some cases by itself destroying 80 per cent, of eggs. With soap, 

 4 lb. to 100 gallons (B.L. 40, 1-1,200), 100 per cent, mortality has been 

 shown. A new combination with nicotine extract and oleic acid has been 

 brought forward. Olein, from which the acid is made, is the chief constitu- 

 ent of the fatty oils, such as olive-oil, whale-oil, etc. 



Soluble Sulphur (a sodium sulphide) is advocated from several quar- 

 ters, but is not generally recommended. If used, it appears that calcium 

 arsenate is safer than lead arsenate in combination. The formula suggested 

 is: 2^/^-31^ lb. soluble sulphur; ly^ lb. calcium arsenate; 15-20 lb. hydrated 

 lime; 100 gallons water. Liver of sulphur (potassium sulphide) cannot be 

 used with arsenicals. 



Residues from Spraying.- — Experiments have been conducted to show 

 the effect of feeding hay cut from beneath trees sprayed with arsenicals. 

 With cattle, no effects at 3 lb. arsenate to 50; symptoms of poisoning, 6-50; 

 serious, 10-50. The same applies to sheep, but not so with poultry. As to 



