G09 



Trebinski (Dr. I.). 0T4eTi> 3a 1914 r. o fltflienbHOCTM CraHuiii 

 OxpaHbl PaCTeHJM BTj BapuiaBt. [Report for 1914 on tlie work 

 of the Station for the Pi-otection of Plants in Warsaw.] 

 Reprint from « EwerOflHUKlj Bapili. 05lM. Cafl.» [Warsaw 

 Horticultural Society s Annual for 1914], Warsaiv, 1915, 88 pp., 

 5 figs. 



The third annual report of the Station records experiments begun 

 in 1913 [see this Review, Ser. A, ii, p. 514] with spraying operations 

 against Chermes abietis, Kalt. These were repeated, the insecticide 

 used being a mixture of tobacco extract with soap emulsion, which 

 is prepared as follows : — 1 lb. of machorka tobacco is boiled in 2| gals. 

 of water and left to stand for 24 hours ; 1 lb. of green soap is emulsified 

 in the same quantity of water and, before being used, both these 

 solutions are mixed in the proportion of 4 volumes of the tobacco 

 extract to 3 volumes of the emulsion, the whole being made up to 

 40 volumes with water. Of 12 fir trees sprayed with this preparation, 

 no galls were observed at the end of summer on 10 of them, while 

 the two others had only a few galls ; a small number of galls were 

 noticed on all the unsprayed control trees. The total destruction of 

 this pest can, however, only be attained after several years of spraying. 

 A table is given showing the results of spraying experiments against 

 Aphids. A 2 per cent, solution of common washing soda with 2 per 

 cent, by volume of linseed oil destroyed Aphis cardui, L. (pruni, 

 Koch), on plums, A. ponii, De Geer {mali, F.) on apples, and A. cerasi, 

 F., on blackberries. A 2 per cent, emulsion of linseed oil destroyed 

 the majority of Aphids on plum trees, though it damaged the leaves 

 at the tips of the shoots. A 2 per cent, solution of soda with 1 per cent, 

 by volume of linseed oil destroyed all the Aphids on plum trees without 

 damaging the foliage. A 6 per cent, solution by volume of Scalecide 

 was effective, but scorched the leaves of apple and cherry trees, though 

 not those of plums or sloes. A half per cent, solution by volume of 

 lysol destroyed only a small rmmber of Aphids. The same solution 

 of lysol with half per cent, by volume of linseed oil destroyed all the 

 Aphids on plums without damaging the foliage, though on apples, 

 the 3^oung leaves were scorched. It is considered that 1 per cent, 

 solution of washing soda with 1 per cent, of linseed oil is the best of all 

 these insecticides. Some experiments were conducted with injections 

 of carbon bisulphide into the soil, and even an injection of 10 cc. at a 

 distance of one inch from strawberry plants did no damage whatever 

 to them ; it is possible that this result was due to the heavy soil. 

 An injection of occ. of carbon bisulphide at a distance of 2 inches from 

 wild apple trees caused scorching of the leaves, while an injection of 

 the same amount at a distance of 1 inch resulted either in the death of 

 the trees, or in serious scorching and dropping of the foliage. Spraying 

 experiments against Eriosoma lanigerum on apple trees were also 

 carried out ; two heavily infested trees were sprayed on 24th March 

 with kerosene soap emulsion (1 lb. of soap, 1 lb. of kerosene and 1 

 gallon of water), the spraying being repeated on the 31st of thart month, 

 with the result that this pest was not observed on these trees in April 

 and May. Two trees were sprayed with a solution of 1 part of Scalecide 

 in 6 parts of water, also on the above dates, with the same result. 

 Two trees were sprayed with a commercial preparation sold as 

 (C208) D 



