432 



Onrust (K.). Ritnaalden en Boonen. [Wireworms and Beans.] — 

 Tijdschr. Phntenziekten, Wageningen, xxv, no. 4, July 1919, 

 Bijblad pp. 17-19. 



Serious injury to beans by wireworms was checked by placing slices 

 of potato in the ground as traps. Skewers stuck through the slices 

 fnade them easy to find. A useful preventive measure consists in 

 damping the seed with petroleum before planting. 



Marchal (P.). Le Cycle ^volutif du Pueeron lanigere du Pommier 

 {Eriosoma lanigerum, Hausmann). — C.R. hehdom. Acad. Sd., 

 Paris, clxix, no. 5, 4th August 1919, pp. 211-216. 



The life- history of Enoso7nalamgerum, Hausm., as recorded in North 

 America, is reviewed and compared with results obtained in France 

 where this Aphid seems to have altered its habits since its importation 

 about 100 years ago. In France the entire life-cycle is spent on 

 the apple tree, propagation being maintained by means of the 

 parthenogenetic reproduction of the hibernating forms. All attempts 

 to induce the insect to return to its American food-plant, JJlmus 

 americana, have proved unsuccessful. This is probably accounted 

 for by the scarcity and occasional total absence of this food-plant 

 in France, resulting in such changes in the plasma of the insect as to 

 make its maintenance on U. americana impossible. An allied species, 

 here described as Eriosoma uhnosedens, sp. n., does exist in France, 

 on elm trees, but is morphologically and biologically distinct from 

 E. lanigerum. This species lives in the spring in colonies on JJlmus 

 campestris only, never on U. americana, and does not require migration 

 to another plant to complete its life-cycle. The winged forms appear 

 in the deformed buds of the elm in the summer and produce a mixed 

 generation, composed both of sexual and asexual individuals, as in 

 the case of E. lanigerum. 



Vayssiere (P.). Quelques Proc6d6s de Destruction des Acridiens et 

 leur Application. — C.R. hehdom. Acad. Sci., Paris, clxix, no. 5, 

 4th August 1919, pp. 245-248. 



Owing to recent ravages by the locusts, Dociostaurus ynaroccanus, 

 Calliptamus italicus and Schistocerca tatarica, official missions were 

 organised to conduct experiments with a view to controlling these 

 pests of agriculture. The work was carried out in Morocco and 

 the South-East of France and various methods were tried, of which 

 full details are given. 



The conclusions arrived at are that the best means of preventing 

 invasion is to use flamethrowers over the whole infested area the 

 moment the young hoppers are formed, provided there is no danger 

 of fire. Alternative methods are the use of a spray consisting of 

 a solution of 50 per cent, chlorpicrin and the use of arsenical poison- 

 baits in places where animals are not likely to graze. 



It is suggested that systematic scientific control measures on these 

 lines should be undertaken ; for this purpose a Committee should 

 be organised by the various countries likely to be most interested, 

 similar to the already existing South African Central Locust Bureau 

 or the Defensa Agricola of Montevideo. 



