208 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
Apple Trees, A Blossom Wilt and Canker of. By H. Wormald, M.Sc, 
A.R.C.Sc. (Ann. Appl. Biol. iii. April 1917, pp. 159-204; 8 figs.). — Great loss 
is caused to fruit-growers in the S.E. of England by a " Blossom Wilt and Canker 
of Apple Trees." The open flowers are the seat of infection, as the fungus 
attacks the tissues of the flowering spur, destroying the leaves and inflorescence, 
sometimes infecting the branch and cankering it. Pustules of conidia are 
produced in the winter and spring following from the dead spurs, and the falling 
conidia cause a new outbreak through infecting the opening flowers. Infection 
does not appear to take place through wounds. 
The disease may be checked by cutting out all dead spurs and cankers before 
the blossoms open. To be effective, the brown and dead wood and bark must be 
removed thoroughly. 
Spraying must be done before the flower buds open, and must be capable 
of destroying the powdery conidial stage, or at least of preventing the conidia 
from falling during the time when the blossom is open and receptive. Lime- 
sulphur wash has not given favourable results. Bordeaux mixture, on account 
of its slightly better adhesive properties, gave a little better result. Ammonium 
sulphide solution (see Jour. Agr. Sci. vii. pp. 473-507) and soft soap, 
applied as late as possible before the flowers opened, killed the surface layers 
of the pustules. The temporary prevention of the fall of conidia in this way 
during the critical period of infection offers the most promising field for further 
experiment. 
The causal organism is a grey Monilia, included under Monilia cinerea 
Bon, distinguishable from M. fructigena. — R. C. S. R. 
Aquilegia, A New Hybrid. By T. D. A. Cockerell (Bot. Gaz. Nov. 1916, 
pp. 413). — The cross was made between Aquilegia chrysantha Gray (a garden 
strain) with A. desertorum (Jones) Cockerell, from Santa Fe Canyon, New Mexico, 
The following is a description of a typical flower : — 
Flower nodding. Sepals about 19 mm. long and 8 mm. broad, pink, with a 
faintly purplish shade, or the apex distinctly purplish. Petals 30 mm. long (to 
end of spur), 8 mm. wide near apex, broadly truncate and sub-marginate apically ; 
apical 10 mm. cream colour, spur rose-pink ; spur broader basally than in 
A. desertorum. 
We may give it a simple Mendelian interpretation by saying that the dominant 
characters are the spur-length of A, desertorum and the flower width of A, 
chrysantha. — R. J. L m 
Arsenate of Lime as an Insecticide. By W. M. Scott {Jour. Econ. Entom. 
viii. p. 194; April 1915)- — Arsenate of lime would be considerably cheaper than 
lead arsenate, and could be made at home. The author and others report 
insecticidal results following its use equal to those obtained by the use of 
lead arsenate, generally with safety to the foliage, though occasional burning 
resulted. The material certainly merits trial against the lead arsenate, and 
can be made by adding sodium arsenate to slaking lime, decanting the liquid 
which contains caustic soda in solution before mixing with Bordeaux mixture, 
lime-sulphur, or water (2 lb. to 50 gallons) for use. — F. J. C. 
Arsenates, Toxic Values and Killing Efficiency of the. By A. L. Lovett and 
R. H. Robinson (Jour. Agr. Res. x. pp. 199-207 ; July 1917). — This paper 
deals with the results obtained in a study of the relative toxic value of pure 
samples of lead hydrogen arsenate, basic lead arsenate, and calcium arsenate 
in poison sprays as insecticides. 
It was found that lead hydrogen arsenate has a higher killing efficiency 
(upon caterpillars), at a given dilution, than either calcium or basic lead arsenate. 
A longer time is required to kill mature caterpillars than the small forms. All 
the arsenic devoured by the insects in feeding upon sprayed foliage is not 
assimilated, but a portion is excreted. This amount varies with the arsenate 
used ; lead hydrogen arsenate was assimilated readily and most of the arsenic 
was retained in the tissue, but in the case of basic lead arsenate the greater 
amount was excreted. It was found that about 0-1595 milligram of arsenic 
pentoxide is required to kill 1000 small tent caterpillars, and about 1-84 gram 
of arsenic pentoxide to kill 1000 mature tent caterpillars, irrespective of the 
particular arsenate used as a spray. 
Calcium arsenate is not suitable as a spray, because of its burning effects 
upon the foliage. — A. B. 
Artichoke, Jerusalem (Jour. Soc, Nat. Hort. Fr. vol. xvii. p. 115, Aug. 1916). — 
This vegetable might profitably be much more extensively grown. It flourishes 
