199 



applicable to groves where the insects are excessively numerous ; in 

 others two applications should be sufficient. For the greatest economy 

 and efficiency 200-250 lb. pressure is preferable. Thorough drenching, 

 especially of the outer portions of the trees, is essential. 



Sanders (G. E.) & Kelsall (A.). Dusts and Dusting for Insect and 

 Fungus Control. II. — Scientif. Agric, Gardenvale, Quebec, ii,no. 1, 

 September 1921, pp. 7-14. [Received 11th February 1922.] 



From the results of many experiments described in detail it is 

 evident that dusts containing copper and arsenic are effective in 

 controlling biting insects and also black spot disease under Nova 

 Scotia conditions. Some commercial Bordeaux powders are possibly 

 as effective as the copper-arsenic dust, but can never be as cheaply 

 made. Sulphur-lead-arsenate dust is slightly more expensive than the 

 spray, while the latter is more expensive than copper-arsenic dust. 

 Dusting possesses certain definite advantages over spraying for biting 

 insects, and therefore it seems inevitable that copper-arsenic dust 

 must in the future play an important part in plant pest suppression. 



ToTHiLL (J. D.). Natural Control Investigations in Canada. — Scientif. 

 Agric, Gardenvale, ()/^t;6i?c, ii, no. 1, September 1921, pp. 20-22, 

 3 figs. [Received 11th February 1922.] 



The introduction into Canada of the natural enemies of certain 

 well-known pests for purposes of control is reviewed. In addition to 

 those dealt with in previous papers [R.A.E., A, iv, 178; viii, 147], 

 mention is made of a predacious beetle that has recently been intro- 

 duced against the oak looper [Ellopia somniaria], which periodically 

 defoliates oak trees in the neighbourhood of Victoria. The result is 

 not yet known. 



Brittain (W. H.). The Apple Sucker {Psylla mall, Schmidb.) in 



Nova Scotia. — Scientif. Agric, Gardenvale, Quebec, \i, no. I.Septem- 

 ber 1921, pp. 22-24," 2 figs. [Received 11th February 1922.] 



The present distribution of Psylla mali, Schmidb. (apple sucker) , in 

 Nova Scotia, its habits and seasonal history, the damage caused, and 

 remedial measures are discussed [R.A.E., A, ix, 385]. Besides 

 nicotine spray or dust mixtures, a heavy lime wash may be applied 

 to the trees when the buds are swelling and begin to show green at the 

 tips. The wash consists of 100 lb. lime, with 20 lb. salt to 100 gals, 

 water. A second application should be made as soon as the first is 

 dry. Though this method is very troublesome, as all the smallest 

 twigs must be covered so that any eggs on them receive a thorough 

 coating, it will be found to give good results. 



List (G. M.) & Newton (J. H.). Codling Moth Control for certain 



Sections of Colorado. — Colorado Agric Expt. Sta., Fort Collins, 

 Bull. 268, July 1921, 31 pp., 6 plates, 5 figs. [Received 11th 

 February 1922.] 



Much information and useful recommendations against Cydia 

 pomonella (codling moth), as applying especially to Delta County and 

 all other sections of Colorado except the lower Grand Valley, are given 

 in this paper. 



