REPORT OF TEE ENTOMOLOGIST AND BOTANIST 203 



SESSIONAL PAPER No. 16 



vigorously. As soon as the sulphur paste is poured on to the slaking lime, add the 

 solution of lye, with such further quantities of water as may be necessary, stirring 

 and mixing, until all bubbling ceases. There is now an orange-yellow, pasty, homo- 

 geneous mass, which can be diluted to the requisite volume, either at once or at any 

 subsequent time, if kept out of contact with the air. 



As far as one can judge from what might be called the chemical or physical point 

 of view, this wash should prove equally effective with that prepared by boiling. 



F. t: s. 



In an excellent bulletin just issued by Prof. J. B. Smith, of New Jersey, entitled 

 * Insecticides and their use,' this lime, sulphur and soda wash is mentioned and some 

 valuable suggestions are made. Prof. Smith says: 'This wash has been found quite 

 effective, but it is not so good as the boiled mixture, and costs a little more.' He also 

 draws attention to the fact that warm water must be used as well as a good quality of 

 stone lime and of caustic soda, and further that it must be remembered that a can of 

 lye does not equal a pound.* He further states that ' all these combinations of lime 

 and sulphur are more or less unstable and sooner or later the lime settles and the sul- 

 phur forms long spicules. When this occurs, the mixture is ineffective in proportion 

 as the sulphur has become separated out. The best boiled combinations become use- 

 less in forty-eight hours, and in all cases the wash is most effective just after it is 

 made,' 



The above extracts from Prof. Smith's bulletin indicate the importance of using 

 the lime and sulphur washes while fresh ; but the statement that ' the best boiled com- 

 binations become useless in forty-eight hours,' is probably too sweeping. 



A point upon which too much stress cannot be laid is the great importance of 

 washing out thoroughly all pumps and hoses used for spraying caustic or corrosive 

 insectide and fungicide washes. 



FOREST AND SHADE TREES 



Forest insects and those which attack shade trees in cities, have been, on the whole, 

 less injurious than usual during the past season. There were, however, one or two 

 outbreaks which require mention. The White-marked Tussock-moth has increased 

 very much in the cities of Toronto, Montreal and Kingston, so much so that remedial 

 measures are now urgently needed, or the beautiful shade trees in those cities will suffer 

 irreparably at no distant date. Something has been done in the past by the city 

 authorities to control this insect, but of late years they seem to have relaxed their 

 efforts, and the insect is increasing in numbers. A remarkable outbreak of the Maple 

 Soft Scale (Pulvinaria innumerahilis, Rathvon) occurred on shade trees in the cities 

 of London, Woodstock and Hamilton, as well as in other places in south-western On- 

 tario. The well known Fall Webworm 

 (Hyphantria iextor, Harr.), which for some 

 years has been occurring only in small numbers, 

 during the last season increased sufficiently in 

 most parts of the Dominion to attract general 

 attention. The unsightly webs were very con- 

 spicuous in British Columbia and in many 

 places in Ontario and Quebec. The webs of 

 the caterpillars are so easily seen that this in- 

 sect, if attended to, can be controlled with com- 

 parative ease, by spraying the trees with poison- 

 ous applications or by cutting off the webs, 

 each of which contains a whole colony of 



jijg^ 20.— The Fall "Webworm : a, cater- 

 pillar ; b, pupa ; c, molh. 



♦The contents of several cans of concentrated lye which were examined here In no case 

 Quite came up to 1 lb. avoirdupois. 



