132 



Contrary to the results obtained by Parrott [R.A.E., A, ix, 352], 

 colonies of the woolly apple aphis [Eriosoma lanigeruni] were completely 

 eradicated on small trees with diist blown from a distance of 3 or 4 feet 

 with not enough air pressure to disarrange the waxy covering of the 

 insects. The dust remained attached to the wax. though it was hardly 

 visible to the naked eye. 



Campbell (R. E.) & Nlxox (W. H.). Two Mechanical Devices Sor 

 controlling Western Cucumber Beetles. — //. Econ. Ent., Geneva, 

 N.Y., xiv, no. 5, October 1921, pp. 400-404, 1 fig. [Received 

 13th January 1922.] 



Diahrotica soror, Lee. (western twelve-spotted cucumber beetle), 

 causes considerable damage in California every year. It is a universal 

 feeder and attacks such crops as beans, cucumber, lucerne, beets, 

 pumpkins and melons. The cucurbits are injured by the destruction 

 of stems and leaves of the young plants ; in lucerne and beets the foliage 

 is damaged, and in beans the foliage, blossoms and pods are attacked. 

 In some cases less than 50 per cent, of the pods develop in consequence, 

 and in several fields of wax beans the injured pods amounted to 

 60 per cent, on some plants, with an average loss of 28 per cent. 

 Most remedies tested have proved unsatisfactory. In consequence 

 of the beetle's habit of flying up when disturbed, a device constructed 

 on the lines of a hopper-dozer was tried, but did not give the success 

 hoped for, owing to many beetles escaping over the top. An apparatus 

 has now been devised by which 3,500 beetles were caught per acre. 

 The disturbed beetles strike against a screen and fall back into a 

 trough containing oil. The machine is described in detail, with an 

 adaptation of it for use in the case of crops grown on small mounds. 

 The total cost of material is only about 305. and it can be easily and 

 quickly constructed. It may be used for infestations of any low 

 growing crop such as beans, beets, cucumbers, etc., grown in rows, 

 and such crops as lucerne until it is about half grown. 



During 1917 and 1918 D. soror and D. trivittata, Mann., caused serious 

 injury to pumpkins and squashes, but the damage was successfully 

 checked by means of this machine. A small hand machine for use 

 while the plants were small enough to be covered by it was also found 

 effective. 



Severin (H. H. p.), Hartung (W. J.), Schwing (E. A.) & Thomas 

 (W. W.). Experiments with a Dusting Machine to control the Beet 

 Leafhopper {Eutettix tenella Baker) with Nicotine Dust. — 



//. Econ. Ent., Geneva, N. Y., xiv, no. 5, October 1921, pp. 

 405-410, 1 plate. [Received 13th January 1922.] 



Dusting experiments against EtUetlix tenella, Baker, carried out 

 in 1919, 1920 and 1921 are described. Where the fields are not isolated, 

 invasions from one field to another may occur, but in the spring most 

 of the adults seen in flight are females from the plains and foothiUs 

 entering the beet fields for oviposition. The percentage of curly leaf 

 increases rapidly with the appearance of the summer generations ; 

 this is not the case when the .spring brood invades the beet fields unless 

 the pest is unusually abundant. Dust mixtures should therefore 

 be tested when the spring brood first makes its appearance in the beet 

 fields. 



