474 



JOUENAL OF THE ROYAL HORTICULTURAL SOCIETY. 



the whole problem of obtaining disease-resisting plants is complicated 

 by many factors, not the least of which is the possible mutation of 

 the disease-resisting organism. — F. J. C. 



Plant Enemies in April and their Destruction. By M 



Schwartz (Gartenflora, vol. Ix. pt. 8, pp. 164-170). — Wireworms 

 and the larvae of the cockchafer are destroyed by pouring carbon 

 disulphide into holes bored in the ground, taking care to avoid the 

 neighbourhood of young plants. Mice and voles are caught in traps, 

 x^pple trees are sprayed v/ith the following mixture : Tobacco extract 

 3 parts, soft soap 6 parts dissolved in 30 parts of water, methylated 

 spirits 5 parts, dilute with 150 parts of water. Cankered parts of the 

 stem and branches are painted with linseed oil. Other plants may be 

 sprayed with a mixture of tobacco extract and soft soap. The eggs of 

 moths and butterflies are moistened with petroleum, and the nests of 

 the tent caterpillar are destroyed by means of a brash dipped in oil. 

 Spraying with a mixture of hellebore powder 1 lb., soft soap, 1^ lb. 

 in 30 gallons of water prevents the ravages of caterpillars. — S. E. W. 



Plants, Insect-catching". By M. J. Kinchel d'Herculais. (Jour. 

 Soc. Nat. Hort. Fr. series iv. vol. xii. Feb. 1911, p. 77). — An account 

 of certain South American and Central Asian plants bearing insect- 

 catching flowers, with a description of the mothod in which the 

 captures are effected. It is pointed out that with these plants fertiliza- 

 tion by insects is obviously impossible, the visits of such insects being 

 fatal to themselves and often injurious to the flower by reason of the 

 dying stniggles of the larger species. — M. L. H. 



Pollination of Pear Blossoms. By E. E. Prescott {Jour. Agr. 



Vict. Jan. 1911, pp. 1-10). — Some varieties of pears are known to be 

 self-sterile, sometimes permanently and sometimes only according 

 to climate or locality, or under certain conditions. Victorian growers 

 are familiar with this peculiarity in such pears as ' Winter Nelis,' 

 ' Keiffer's Hybrid,' and ' Gansel's Bergamot.' Yet it is well known 

 that in some localities and countries even these fruits are self-fertile; 

 thus whilst ' Beurr^. Clairgeau,' 'Howell,' 'Souvenir du Congres,* 

 and ' Louise Bonne of Jersey ' are considered to be self-sterile in 

 America, in Victoria no trouble is found in the setting of fruit in these 

 varieties of pear, and whilst 'Keiffer's Hybrid' is considered self- 

 fertile in America, it is found in Victoria to be generally impossible 

 iiO induce this tree to produce even a fair crop without the aid of cross- 

 pollination; whilst very frequently it happens, that without artificial 

 aid the trees of this variety never bear fruit at all. 



It is probable that pollen may be more profuse and more active 

 in some seasons than in others. In Victoria in 1910 the average time 

 of pears in bloom from first to last was about nineteen days ; while, in 

 sheltered locations, the time is extended to from four to six days longer. 



Where at present only one variety of pear is grown, or where the 

 varieties do not concur in their time of blooming, it is necessary that 



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