136 



CouANON (G.) & Salomon (E.&K.). L'Emploi de I'Eau chaude centre 

 les Parasites de la Vigne. [The Use of Hot Water against Vine 

 Pests.] — Rev. Viticulture, Pam, xlv, no. 1171, 7tli December 1916, 

 pp. 372-373. 



A series of experiments in tlie use of hot water as a control for the 

 larvae of Clysia ambiguella and Polychrosis botrana were made by the 

 authors on a vine trellis in July 1916, when the second period of 

 oviposition of the moths should have been completed. The apparatus 

 used was an ordinary garden syringe wdth a flat rose, the water being 

 drawn from a Vermorel boiler. The temperature in the shade was 

 about 73° F. 



When water at 168° F. in the syringe or 158° F. by the time it 

 reached the grapes was used, the fruit was destroyed. At 150° F. in 

 the syringe and 146° F. on the grapes, no harm was done to either vines 

 or leaves. 



A similar experiment on a pear espalier very severely attacked by 

 honey-dew and sooty fungus (Cajmodium), using water at 158° F. in 

 the syringe and 151° F. on the leaves, was most successful. 



Feytaud (J.). Recherches sur les pieges-appSts. III. Le Pourcentage 

 des Sexes. [Experiments with Bait-traps. III. The Percentage of 

 the Sexes.- — Bull. Soc. Etude Yulg. Zool. Agric, Bordeaux, xv, 

 nos. 11-12, November-December 1916, pp. 113-118. 



This paper supplements others already abstracted [see this Revieiv, 

 Ser. A, iv, p. 309, 492]. 



Various authors are agreed that the usual percentage of the sexes of 

 Clysia ambiguella and Polychrosis botrana is 40 females to 60 males. 

 The proportions among the moths taken from various traps is found to 

 be about the same, a greater proportion of females being captured 

 during fine and calm weather [see this Review, Ser. A, i, p. 416] ; the 

 month of July is therefore usually the best time for bait-traps. The 

 atmospheric conditions being the same in various vineyards in one 

 locality, the relative percentage of the sexes captured might be expected 

 to be the same throughout. This however is not the case, and further 

 investigation has shown that in vineyards where the traps are uniformly 

 distributed the percentage of females captured is higher than in those 

 where the traps are set in groups widely mterspaced. The reason 

 seems to be that the females have neither the fine perception exhibited 

 by the males for the odour emanating from the traps nor sufficient 

 activity to fly to the centres of attraction, and are most easily captured 

 when the traps are set too closely (8 to 12 feet apart) for them to escape 

 their action. Investigation has also demonstrated that the type of 

 vessel used to contain the bait influences the proportion of the sexes 

 captured ; a vessel which admits of only a small surface of liquid, and 

 of which the walls are considerably sloped is found to capture more 

 females in proportion to the number of males than one with straighter 

 sides and a larger surface of liquid. This is probably accounted for 

 by the greater agility of the males and the attitude in which they alight 

 on the surface of the liquid, all of which conditions facilitate their 

 escape when this is at all possible. 



