448 



at dilutions of 1 to 800-1000. Free copper sulphate, which causes^ 

 injury to fruit and foliage, was absent from the mixture. The foliage 

 of apple, pear, peach, etc., showed no sign of injury when examined, 

 although the weather variations were sufficient for leaf injury to 

 become evident within the three weeks during which the plants were 

 under investigation. The combination was analysed for nicotine two 

 hours after making ; the whole of the latter was recovered. Instances 

 of damage to foliage can be explained by the fact that the combination 

 will probably not prevent any injury that the Bordeaux mixture would 

 cause if used alone. Numerous reports of the successful use of the 

 combination have been received. 



Parrott (P. J.) & ScHOENE (W. J.). The Insecticidal Properties of 

 various Sulphides and Polysulphides {Abstract). — Jl.Econ.Entom., 

 Concord, vii, no. 2, April 1915, pp. 204-205. 



Sulphides and polysulphides of sodiiim, potassium, calcium and 

 barium have been used for the last few years as spraying mixtures. 

 Except calcium, they can be obtained in a powdered state ; calcium 

 sulphides are obtainable in liquid preparations. The amount of sulphur 

 in \hese insecticides varies greatly ; for example, in sodium prepara- 

 tions it ranges from 1-79 to 58- 92 per cent. Experiments have been, 

 conducted in which the compounds have been tested on the basis of 

 their sulphur content, the sulphides and polysulphides of the different 

 bases being used at varying strengths to give similar ratios of sulphur 

 respectively in the dilute mixtures. In experiments against the 

 San Jose scale, using the compounds at the rate of 4| oz. sulphur to a 

 gallon, there were variations in effectiveness on individual trees. As 

 gauged by the blemishing of fruits, the production of young scales 

 and the infestation of new wood, one preparation had no perceptible 

 advantage over another. The work in general so far points to the con- 

 clusion that the strength of a preparation with regard to its svdphur 

 content is a more important consideration than the nature of the base 

 of the sulphides and polysulphides. Assuming that the bases act 

 equally against the scale, the chief factors are the absence of injury 

 to foliage, when combined with lead arsenate, and economy, in which 

 respects calcium and barium sprays are most advantageous. None 

 of the compounds alone were harmful to leaf-eating caterpillars or 

 beetles ; when mixed with lead arsenate, the compounds of sodium 

 and potassium showed more rapid toxic effects, but were liable to 

 cause injury to the foliage. Various substances, eg., glue, soap, 

 glycerine, oil emulsions, can be combined with spraying mixtures to 

 give penetrating and adhesive properties. With the compounds under 

 discussion, no marked results have been observed, except where soap 

 and oil emulsions were used with sodium and potassium sulphides 

 against aphids, or oil emulsion with the same sulphides against the 

 San Jose scale {Aspidiotus perniciosus) . The principal gain in the 

 latter case appears to be in an increased rate of toxicity. 



Scott (W. M.). A New Contact Insecticide. — Jl. Econ. Entom.y. 

 Cmcord, viii, no. 2, April 1915, pp. 206-211. 

 Lime-sulphur, though unquestionably the most important and the- 

 most largely used contact insecticide and fungicide, is bulky and heavy 



