I98 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
" cover washes," imprisoning or impeding the movements of insects, but fre- 
quently their action is complicated by the addition of substances likely to have 
specific insecticidal power, so that it is difficult to decide to which action good 
results are due. 
Three cases are reported on : — 
(1) A large apple orchard was sprayed very late in winter with lime wash, an 
adjacent orchard being left unsprayed. The former was remarkably free from 
aphides and apple sucker, which were present abundantly in the latter. 
(2) Another large orchard was sprayed in sections with self-boiled lime-sulphur. 
The last section to be sprayed was done when blossom was nearly open. This 
was freest from aphides and suckers and bore the heaviest crop of fruit, while the 
first sprayed section was severely attacked by these insects and early lost its 
foliage. 
(3) A damson orchard sprayed in sections with a lime wash containing water- 
glass. Here again the last sprayed section, done so late that injury to the blossom 
was feared, gave a good crop, the trees being free from aphides, while the first 
sprayed section was badly attacked by aphides and bore little fruit. 
These results are discussed, and it is pointed out that the best results were due 
to the late application and that " it appears evident that their insecticidal action 
must have been due primarily to their mechanical or covering properties." 
G. C. G. 
Manganese, Its Action in Soils. By J. J. Skinner and M. X. Sullivan 
(U.S.A. Dep. Agr., Bull. 42, Apr. 1914). — The authors studied the effect of 
manganese chloride, sulphate, nitrate, carbonate, and dioxide on poor and good 
soils. All these salts, when applied in amounts from 5 to 50 parts of manganese 
to the million of poor soil, had a stimulative effect which was not seen when larger 
quantities were applied (when indeed it was even harmful) nor on productive 
loam. They increased growth and the oxidation power of the roots in extremely 
poor soils, but only oxidation was increased in good soils while growth was 
decreased. They consider the good effects produced in poor soil are due to the 
promotion of oxidation both in plant and soil. Manganese does not produce good 
effects in acid soils, which are unfavourable to oxidation processes, and the 
authors consider that manganese is unlikely to prove profitable in soil in need of 
liming. (See Journ. R.H.S. xl. p. 94.) — F. J. C. 
Marguerite Fly, The. By M. T. Smulyan, B.S. {U.S.A. Exp. Stn. Mass., 
Bull. 157, Nov. 1 91 4; 3 plates). — The marguerite fly or chrysanthemum leaf 
miner (Phytomyza chrysanthemi Kowarz) is, as far as is known, a native insect 
and is essentially a greenhouse pest. It may be controlled by spraying with the 
nicotine solutions " Black-leaf 40," " Nicofume " liquid, and " Nicoticide," 
diluted from 400 to 450 times in water and applied at intervals of eleven or 
twelve days, or oftener if the temperature in the greenhouse is higher than that 
at which marguerites are usually kept. — V. G. J. 
Mediterranean Fruit Fly in Bermuda, The. By E. A. Back (U.S.A. Dep. 
Agr., Bur. Entom., Bull. 161, Dec. 191 4). — This bulletin discusses the history of 
the fruit fly in Bermuda, the life-history, and the possibility of eradicating it 
from Bermuda by strict quarantine regulations. — V. G. J. 
Melon Aphis (Aphis gossypii Glover), A Method of Controlling. By C. E. Durst 
(Illinois Exp. Stn., Bull. 174, 7 pp. ; 3 figs.). — A preparation known as " Black 
Leaf 40 " (nicotine sulphate) proved " thoroly " successful in controlling the 
pest. — E. A. Bd. 
Mode Of Infection of Larch Canker. By Sir John Stirling-Maxwell, Bt. 
(Trans. Roy. Scot. Arbor. Soc. xxix. pt. 2, pp. 131-133 ; 1915)- — Mr, Hiley 
starts with the assumption (which he undertakes to prove in a future article, 
but which few foresters will dispute) that the young shoots are not liable 
to attack until the first year's growth is complete. Next he discusses the 
various methods of infection to which the shoots may fall victims in their 
second year, but dismisses such attacks as relatively unimportant, since the 
side branches of the larch die quickly, and the main shoot, if affected early, is 
usually killed and replaced by a lateral. He then turns to the really important 
part of his subject, namely the origin of the more destructive cankers on the 
mam stem. — A. D. W. 
