0. H. W11.1.IAM8 243 



Essex, ill July, 1013, gave no indication of resistance, except that due 

 to time of planting. In Report on Field Experiments, 1912, East 

 Anglian Institute of Agriculture, Chelmsford, it is stated that 'Tele- 

 graph' was destroyed by thrips, while 'Gradus,' 'Essex Star,' 'Alder- 

 man' and 'Blue Seedling' gave eood crops. 



Artificial Control. 



The habits and life history of this insect make the application of 

 remedial measures of great difficulty. Sprays will not reach the adults 

 or larvae in the flowers, and during the winter the great depth to which 

 the larva descends (they have been found in the wild state more than 

 ten inches below the surface) makes the application of gas lime or soil 

 fumigants of doubtful value. In March of this year numbers of larvae 

 were found deep down in a plot of soil which had been heavily limed 

 last autumn. 



When plants are attacked late the larvae, however, are often found 

 in numbers feeding openly on quite large pods. At such a time spraying 

 with any contact spray (soft soap, rosin, etc.) should give good results. 

 On a small scale the following has been found successful 



Stock solution 



Water 1 qrt. 



Soft soap 3 oz. 



Tobacco powder 3 oz. 



The whole boiled for a short time and diluted for use about one part 

 to twenty of water. 



When only a small area is attacked fumigation of the soil during 

 the winter with carbon bisulphide, gas lime, creosote, or such trade 

 products as vaporite or creol should give good results, provided that it 

 is done to a sufficient depth. Experiments are now in progress to test 

 carbon bisulphide-oil emulsion recently described and which it is hoped 

 may prove satisfactory. 



Whenever possible a rotation of crops should be practised and peas 

 and beans grown as far as possible from the areas attacked in the 

 previous year. 



Traps employing benzaldehyde, anisaldehyde and cinnamyl aldehyde 

 as attractive agents, as described by Howlett (1914), were tried and 

 found to be of no use. These aldehydes have no attraction for this 

 species of Thysanoptera. 



Ann. Biol. i. 17 



