370 



the summer use of calcium arsenate, | lb. to 50 U.S. gals., if combined 

 with self-boiled lime-sulphur and nicotine. If self-boiled lime-sulphur 

 is not used, freshly slaked lime, 4 lb. to 50 U.S. gals, of mixture, should 

 be added. Three applications should be made at monthly intervals, 

 the first being at the time the bloom falls. The complete course 

 of treatment therefore is : — Concentrated lime-sulphur (1:9) when the 

 buds swell ; self-boiled lime-sulphur (8:8: 50) with calcium arsenate 

 and nicotine after the petals fall, the same mixture being applied 

 2, 8 and 12 weeks later. Applications of tobacco (nicotine sulphate 

 or Blackleaf 40) and soap cannot be recommended for combating 

 this pest. 



RuGGLES (A. G.). Spraying. — Minnesota Univ. Farm, St. Paul, Circ. 

 no. 48, 1st April 1918, 16 pp., 19 figs. 



This circular discusses stomach poisons such as lead arsenate, 

 Paris green and hellebore, and gives various formulae for poison- 

 baits. Contact insecticides dealt with include soap solution, tobacco 

 extracts and lime-sulphur. 



A new contact insecticide, which shows greater promise than any 

 of the commercial tobacco compounds on the market, is described. 

 This is nicotine oleate and is a combination of a free nicotine extract, 

 such as Nicofume, with commercial oleic acid, often called red oil. 

 Two and a half parts of 40 per cent, free nicotine solution thoroughly 

 mixed mth If parts of red oil wall unite to form this material. A 

 50 gal. spray can be made by diluting ^ pint of nicotine oleate, and 

 is less than half the price of free nicotine spray used at the same 

 strength. It is important that soft water, either rain or distilled, 

 should be used for this spray. While nicotine oleate alone is more 

 effective than the nicotine extracts now on the market, it can be made 

 still more so by emulsifying an oil with it. These emulsions are not 

 recommended when the trees are in leaf. They can be made by mixing 

 10 parts of an oil, such as cotton seed or kerosene, with If parts of red 

 oil, to which is then added 2| parts of 40 per cent, free nicotine solution. 

 This should be shaken thoroughly, and 10 parts more of water should 

 then be added and the mixture again shaken. For mealy bug 

 [Psevdococcus], white fly [Aleiirodes], etc., the solution should be 

 diluted with soft water to make 500 parts. 



General instructions for spraying with both dust and liquid sprays 

 are given, with descriptions and illustrations of the requisite machinery 

 and accessories. A spraying calendar for various fruit and vegetable 

 crops is appended. 



Graham (S. A.). Some Insects Injurious to the Potato. Insects of the 

 Home and Vegetable Garden. Insects Injurious to Small Fruits.— 



Minnesota Univ. Farm, St. Paul, Circs. 47, 49, 50 ; 25th March, 

 15th April, 20th April 1918, 28 pp., 33 figs. 



Potato pests of Minnesota include Leptinotarsa decemlineata, Say 

 (Colorado potato beetle), of which there are two broods a year in this 

 State. Natural enemies include Coccinellid beetles and the larvae 

 of lace- wing flies, wild birds and domestic fowls ; none of these however 

 are a sufficient check, and an arsenical spray should be used as soon 



