386 



the borers were much too well protected behind the leaves. The 

 following figures are given for a station cane-field of 29| acres, which 

 was regularly searched by 11 labourers. It was planted during July 

 and the search for eggs began in the middle of August and lasted four 

 months. In this period 45,098 infested shoots were cut and found to 

 contain 32,605 caterpillars, Scirpophaga, 9,889 ; Diatraea, 7,740 ; 

 Chilo, 4,687 ; Olethreutes, 10,289. The total number of egg-masses 

 was 4,815, of which 4,040 were Diatraea and the remainder Scirpophaga. 

 At the end of the operations, the cane-field was practically free from 

 borers. The opinion has been expressed that, despite such work, pests 

 enough remain to cause such damage that the result is much the same 

 as if no attempt at control had been made and that the cost of control 

 is money thrown away. This very important question does not appear 

 to have been settled one way or the other and the author suggests 

 that it should be thoroughly worked out on two separate cane-fields, 

 one of them to be handled in the ordinary way and the other treated 

 carefully against the borer pests ; the result, financially, does not 

 appear by any means to be a foregone conclusion. This lengthy and 

 interesting paper concludes with a brief description of each of the pests 

 dealt with. 



ToMEi (B.). Norma di Viticoltura con riguardo alle Viti Americana ed 

 air innesto. [Rules of Viticulture with regard to American Vines 

 and grafting.] — Urbino, 1915, 120 pp. 



Thirty pages of this book are devoted to fungus and other diseases 

 of the vine. The life-cycle of Phylloxera on American vines is stated 

 in the form of a genealogical tree, R. indicating the root-inhabiting 

 and G. the leaf -inhabiting or gall-producing stages. A wintering egg 

 laid by a fecundated female at the end of summer or beginning of 

 autumn, produces, in the follo\^dng spring, a larva which attaches 

 itself to the upper surface of the leaf, there producing a gall, in 

 which, after four moults, it lays 600 eggs from which result 

 three generations of insects. The third of these consists chiefly of the 

 G. variety and their progeny, the fourth, are almost all of the R. variety, 

 giving rise to the fifth and sixth generations of purely R. Phylloxera. 

 From a part of the sixth, the hibernating individuals are derived, 

 the remainder consisting of nymphs and pronymphs. The minority 

 of R. in the third generation referred to above, produces entirely the 

 R. variety and their progeny are divided into another generation of 

 R., among which are those that will hibernate, and the nymphs and 

 pronymphs of July and August. These and the other nymphs and 

 pronymphs produce the winged sexuparae, which fly between 2 and 

 5 p.m. and lay eggs on the vine-stocks, producing both males and 

 females. These pair, and four days later the females hide under the 

 bark and, after 24 hours, lay their winter eggs. The whole cycle 

 then begins again. On the European vine, the larva which emerges 

 from the wintering egg \nth G. characters is unable to produce the gall 

 in which the eggs are to be laid to provide for the aerial generation. 

 Grassi has shown that it is unable to descend to earth and take on R. 

 characters, so that the multiplication of Phylloxera on European vines 

 can only take place through the R. type when both varieties of vine 

 are available. The sexuparae oviposit on the American and not on 



