363 



The flowers are cultivated commercially and the powder made in 

 Dalmatia, Japan, Austraha, Algeria and California. It is sometimes 

 adulterated with colouring matter, other species of flowers or any 

 convenient powder, but particularly with the ground stems of the 

 pyrethrum plant itself. A formula is given for determining the 

 approximate amount of added pyrethrum stems in insect powder. 



Although Chri/santhemwn (Pj/rethrum) cinerariaefolium is the plant 

 from which it is usually made, pyrethrum made from C. (P.) roseum 

 and C. marshalli is recognised by the Insecticide Board of the United 

 States Department of Agriculture. 



MoERiLL (A. W.). Entomology. — 28th Ann, Rept. Arizona Agric. 

 Exj)t. Sta.,for Year ended 30th June 1917, Tucson, 31st December 

 1917, pp. 472-473. [Received 23rd June 1920.] 



This report gives the results of experiments with poison baits for 

 the grasshopper, Melanoplus differentialis, the most destructive 

 species in Arizona. Attempts to reduce the cost of the standard 

 formula have abeady been noticed [R.A.E., A, vii, 206]. The new 

 formulae have not been tested against other species of grasshoppers, 

 or the immature stages of M, differentialis. It is of httle importance 

 at what time of day the baits are spread. Grasshoppers rarely travel 

 70 yards and usually not more than 25 yards from where the poison 

 is eaten. The calculations of loss per square yard due to these 

 insects have already been noticed [R.A.E., A, vi, 305]. 



Fromme (F. D.). & Ralston (G. S.). Dusting Experiments in Peach 

 and Apple Orchards. — Virginia Agric. Expt. Sta., Blacksburg, 

 Bull. 223, November 1919, 16 pp., 2 figs. [Received 23rd June 

 1920.] 



Dusting, as compared with spraying, saves time and labour, especially 

 where rough ground hampers the use of the heavier hquid outfits, 

 but it has several limitations in practice in the case of both peaches 

 and apples. The following formulae were used in dusting experiments 

 (the parts being by weight) : — for peaches, sulphm* and lead arsenate 

 90-10, and sulphur, filler and lead arsenate 50-40-10 ; for apples, a 

 Bordeaux dusting mixture and an 80-10-10 mixture of sulphur, filler 

 and lead arsenate. In peach orchards both the dusting mixtures 

 produced a satisfactory control of scab {Cladosporimn carpiophilum) 

 and probably curculio [Conotrachelus nenuphar], but were of only 

 slight value in the control of brown rot {Sclerotinia cinerea) ; conse- 

 quently though they may be used for the first two summer apphcations, 

 they cannot be relied on for the third or subsequent ones. In apple 

 orchards both mixtures produced a satisfactory control of the codling 

 moth [Cydia pomonella], and the Bordeaux dust gave excellent results 

 against blotch {Phyllosticta solitaria) and frog-eye {Sphaeropsis malo- 

 rum) ; but they were httle better than no treatment at all against bitter 

 rot {Glomerella cingnlata). As a result it would seem that neither in 

 the case of apples nor peaches can dusting be regarded as giving a 

 satisfactory general control ; and as its use must therefore necessitate 

 duphcations of equipment, the best results will probably come from 

 the methods and materials the value of which has aheady been proved. 



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