212 SCIENCE PROGRESS 



The report by C. B. Williams on the Froghopper blight of sugar- 

 cane in Trinidad (Mem. Dept. Agric. Trinidad and Tobago, 1, 

 1 70 pp., 1 1 pis.) deserves special mention, and is a valuable study 

 of the relations between outbreaks of the causative insect 

 {Tomaspis saccharina) and the conditions under which the 

 affected crops are grown. The economic entomologist is 

 beginning to realise that work of this nature is likely to open 

 up fresh methods of control. If it is possible to grow crops less 

 susceptible to attack either by attention to cultural conditions, 

 or by the breeding of more or less immune varieties, some of 

 the expense and labour devoted to the application of insecticides 

 might be saved. Entomological Bulletin, No. 827, of the U.S. 

 Dept. of Agriculture deals with insect control in flour-mills. 

 The most satisfactory method for dealing with all classes of 

 mill-infesting insects is the application of heat (i 18° to 125° F.). 

 To carry out this process effectually the installation of radiators 

 or radiation surfaces is necessary. It has been estimated that 

 this can be fitted up sufficiently economically in an average- 

 sized mill to pay in five years for the cost of its introduction. 

 L. Moreau and E. Vinet {Ann. Serv. des Epiphyties, vi, 299-312) 

 report on a series of experiments dealing with the chemotropic 

 method of controlling the moth Clysia ambiguella in French 

 vineyards by means of traps baited with attractive substances. 

 The authors find, as Imms and Husain have found in England, 

 that chemotropic responses are very dependent upon climatic 

 conditions. The maximum numbers of the Clysia were caught 

 just after sunset, and there was a gradual decrease after 10 p.m. ; 

 65* I per cent, of the trapped individuals were females. 



J. F. Illingworth (Journ. Econ. Ent., 14, 238-9) briefly 

 describes some experiments with the use of crude white arsenic 

 (arsenious acid) as a soil insecticide against larvae of the beetle 

 Isodon pundicollis. An application of 80 lb. to the acre gave 

 encouraging results, and it is stated that even such a relatively 

 enormous dose as 200 lb. to the acre had no detrimental effects 

 upon the growing plants. Sugar-cane, for example, grown 

 upon land so treated revealed no trace of arsenic in the sap. 

 Much more extensive experiments, than the author has yet 

 carried out, are needed before the application of a substance of 

 this nature can be advocated. Its effects on the micro-organ- 

 isms of the soil need to be considered, and we also need to know 

 whether arsenical compounds of sufficient strength to be toxic 

 to insects might not soon render the soil infertile. In Soil 

 Science (xi, 305-318), A. Peterson writes on the application of 

 paradichlorobenzine as a soil insecticide with reference to the 

 control of the Pear-tree Borer. 



At a joint meeting of the American Association of Economic 

 Entomologists and the American Phytopathological Society 



