735 



Somes (M. P.). The Acridiidae of Minnesota. — University of Minnesota, 

 Agric. Expt. Sta., University Farm, St. Paul, Technical Bull. 141, 

 July 1914, 100 pp., 4 plates, 11 figs. 



This is an account of the Acridiidae found in Minnesota with keys 

 to the genera and species ; notes and illustrations of the habitat of 

 many species and maps showing their distributon are added. 



ScARioLi (D. G.). Gli Afidi [Aphids]. — Venezia Agricola, Venice, xviii, 

 no. 32, 8th August 1915, p. 3. [Received 11th October 1915.] 



Experiments made by Perrusino of Turin in injecting potassium 

 cyanide into plants with the object of poisoning them and rendering 

 them objectionable to Aphids, failed entirely, the cyanide being 

 decomposed by the plant juices. Some damage was done to the plants 

 at the points of injection and the Aphids only moved away from this 

 part to others ; in some cases the plants were seriously damaged. 

 Phenicated tobacco extract, 1 part in 500 of water, sprayed over the 

 plants soon after dawn is stated to be effective against Aphids ; a little 

 carbonate of soda, added to the mixture to neutralise any excess of 

 sulphuric acid present and to decompose in part the nicotine sulphate, 

 renders the spray more active. It should always be prepared just 

 before use and not kept in stock ready mixed. 



II Piretro Insettlcida. [P\T:ethrum as an Insecticide.] — Rivista di 

 AgricoUura, Parma, xxi, no. 42, 15th October 1915, pp. 660-662. 



Dr. G. Tropea has published in the " BoUettino di studi ed 

 informazioni del R. Giardino Coloniale di Palermo " a detailed account 

 of the cultivation of pyretlirum for use as an insecticide. The plant 

 requires a temperate climate rather warm and dry ; if cultivated in a 

 damp locality, the plant thrives, but the active principle on which 

 its value as an insecticide depends is very slightly developed. It 

 grows well on a dry and stony, calcareous soil and is propagated by 

 seed, of which, even in good samples, 20 per cent, fail to germinate. 

 In places where the winter is not severe, it may be sown in September ; 

 otherwise it is best to wait until 3Iarch ; in a few months plants 

 4 or 5 inches high will be obtained and these will produce a few flowers. 

 These should be planted out in the following spring, about a foot 

 apart. Flowering begins in the second half of May, or later, if the 

 spring be cold and wet, and lasts for two months ; the plants do not 

 all flower at the same time. The flowers are collected by women and 

 children, when they are on the point of opening, as these give a powder 

 of higher insecticidal value than those which are fully opened. When 

 the harvest is over, the plants are cut down and the soil between the 

 rows well dug. Cultivation may go on for from 6 to 8 years on the 

 same land, which must then be ploughed up and used for other crops. 

 Each plant, if well grown, will yield an average of 100 flower-heads 

 or about a ton to the acre when fresh, or 5 cwt. when dried. The 

 flower heads are spread on sheets in a layer 1 to 1\ inches thick and 

 turned 2 or 3 times a day ; they are then ground up. The fresh powder 

 is quite inert and requires to ferment slowly for 2 or 3 months before 

 it becomes active, and should then be kept in hermetically closed 



