563 



air within the bell and produced a damp heat. The bell was provided 

 with a flat bottom which fitted round the trunk of the vine Uke a 

 collar and along this bottom plate the steam entered. A thermometer, 

 the bulb of which was within the cover, indicated the degree of heat 

 and guarded against overheating. On the limit being reached, the 

 supply of steam was cut ofi, the cover being left untouched until the 

 proper time had elapsed. This period lasted from 3 to 4 minutes ; 

 the temperature was 120''-122° F. A vineyard strongly infested with 

 Sparganolhis pilleriana was chosen and 8 cloches were used, 4 being 

 in action whilst the other 4 were being placed or removed. A squad 

 of 3 workmen permitted the work to be quickly done. Radical results 

 were obtained against S. 'pilleriana and Chjmi amhirmclla. Each 

 time a cloche was removed a very great number of dead insects were 

 seen, the quantity being (juite unexpected from the appearance of 

 the stock. Photographic records were taken and are kept at the 

 Station Viticole de Villefranche. Various gases had been tried previous 

 to the steam trials and all had proved defective, inasmuch as they 

 injured the plants more than the pests. When the steam entered 

 the chamber the larvae immediately began to move about and soon 

 fell on the bottom plate, which was heated to 212° F. Dry heat would 

 not be so effective, as the larvae could cause evaporation by breathing 

 quickly and thus contend against the increase of temperature. The 

 difference between the degree of heat recommended here and the 

 considerably higher one advised by M. Semichon is more apparent 

 than real, as in the latter case, contact with the air and also evaporation 

 must certainly cause a considerable loss of heat. M. Semichon himself 

 has advised care in adjusting the time to the temperature, a longer 

 time being only permissible with a lower temperature. The use of 

 cloches has this great advantage : when seeking to escape, the larvae 

 necessarily reach the bottom plate, the great heat of which kills them 

 instantly. The employment of hot water itself was also advised by 

 Vermorel in 1912 [see this Review, Ser. A, ii, p. 375]. 



Semichon (L.). Traitement des vignes d I'eau chaude et aux bouillies 

 chaudes. [The treatment of vines with hot water and hot spray 

 solutions.] — Rev. Vitic, Paris, xliii, no. 1096, 1st July 1915, 

 pp. 9-12. 



Referrmg to MM. Gastine and Vermorel's communication on the 

 use of steam in controlling insect pests [see above], the author considers 

 that steam is preferable to hot water against the larvae, whether they 

 be protected by their cocoons or not, and also against Aphids and 

 other insects which are directly vulnerable. For the destruction of 

 eggs, hot water is more efficient ; it will also be useful against quite 

 newly hatched larvae and in any case its use is exceedingly simple, 

 no special apparatus being necessary as with steam. According to 

 Ohauvigne [see above], the minimum useful temperature of 131° F. 

 is not obtainable in practice where medium or large size areas are 

 concerned, but it must be remembered that the mimite drops of hot 

 Avater only require to rcald the insects superficially and it is not 

 necessary that the whole of the insect's body should be raised to the 

 same high temperature in order to cause death. Splashes of hot water 

 falling on the hand provide a parallel case : the skin is scalded, but 



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