33 



gra])<'s from the bmicln's of four vines, two treated and two untreated, 

 belonginii to the two varieties " dolcetto " and *" barbera." The 

 number of ,i,Ta])es injured or destroyed on the treated '" barbera "' vine 

 were 2G0, on the untreated one, 560, and the corresponding figures ior 

 the *' dolcetto " were 403 and 526. The larvae of C. antbiffueUa were 

 found in far greater numbers on the '' dolcetto " than on the " barbera " 

 variety, though the stocks of both stood in the same rows. It is not 

 known whether this was due to a preference by ('. ambiijtieUa for this 

 variety, or whether it was caused by the earliness of the " dolcetto," 

 or the well known earlier development of C. ambifjuella as compared 

 with P. hotiona. It follows that the effect of the treatment differed, 

 and the applications proved to have been made in good time for the 

 " barbera," but were too late for the " dolcetto." This is an additional 

 reason for growing a single variety on each plot of land in new plan- 

 tations, control being thus much sim])]iHefl. If C. (nuhlgiwlla is more 

 numerous than P. hotrdtut, it is advisable to apply treatment some davs 

 earlier. Many of the grapes of " barbera " treated with tobacco 

 extract were only slightly attacked, whereas the percentage com- 

 pletely spoilt or seriously attacked was much higher oJi the untreated 

 vine. On the treated vine oidy one lar\'a was found to every 8 or 10 

 grapes attacked, while the proportion on the untreated stock was one 

 to every three or four. The results therefore were to reduce by about 

 50 per cent, the number of grapes completely or partly spoilt. 

 The.se results, obtained with two sunmier treatments only, are con- 

 sidered to indicate a promising method of control. 



EscHERiCH (K.). Method of Cockchafer Control used in Germany. 

 — Internal. Rev. Science dc Pni^iice Ayric, Mtlibj. Bull. Agric. 

 Intdl. <t PI. Dis., Rome, vii, no. 6 June 1916, pp. 910-91-2. 

 [Abstract from Zeitschr. f. amjewandte Entomologif, Berlin, m. 

 no. 1. March 1916, pp. 134-156.]. [Received 10th November 

 1916.] 



Extensive experimcTits for the control of Mehhntha inelol&ntha and 

 M. hippocaslani carried out in the Bienwald in the Upper Palatinate 

 are described. This State forest covers several thousand acres and 

 has for many years been heavily infe.sted with cockchafers, widespread 

 damage being .sometimes done. It is composed of Pina.s, larch and 

 Weymouth pine, as well as beech and oak. The comparatively drv. 

 sandy and stony soil, forming dunes, favours the insects, the develop- 

 ment of which has also been fostered by the very mild winter climate 

 and until a few vears ago by bad methods of forestry. The control of 

 cockchafers was begun in 1882, but without satisfactory results. 

 Seventeen years of experience from 1882-1899 showed that the control 

 exercised by birds and mammals is wholly insignificant, while con- 

 ditions are unfavourable to the fungus, Botri/ti.'i tenella. Collecting 

 and trapping the larvae or destroying them in the soil with benzine or 

 carbon bisulphide all proved inadequate methods of control. The 

 present forester proposed in 1899 to destroy these pests by a method 

 based on the fact that at the time of flight and mating they exhibit a 

 marked preference for certain trees growing in the open fields and 

 allowing of easy flight in and around their tops. These trees, in order 

 of importance, are : — Beech, larch, hornbeam, birch and oak. In the 



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