NOTES AND ABSTRACTS, 
to be the cause of dry-rot in the past. No connexion with a species of Nectria 
has been traced. The authors state that the dusting of potatos in the clamp 
with quicklime and sulphur has no preventive value, but the experiments upon 
which this statement is based do not approximate to those in the clamp. The 
fungus more easily attacks the tuber later in the season than early, and the authors 
recommend that no diseased tubers should be planted. The fungus does not 
produce a wilt disease as do some other species of the genus. — F. J.C. 
Potato " Leak," The Control of. By L. A. Hawkins (U.S.A. Dep, Agr., Bur. 
PI. Ind. y Bull. 577, Sept. 191 7, pp. 1-6), — The disease known as potato leak 
is caused by various organisms. Amongst the chief are Rhizopus nigricans 
(Ehrenb.) and Pythium Debaryanum (Hesse), The fungi obtain an entrance 
through wounds in the skin of the tubers and cause complete rottenness in 
the tubers. It is evident from the experiments that removal of all the wounded 
tubers from the stored potatos is the most effective means of control, and care 
should be taken to avoid damaging the tubers when lifting them, — A* B t 
Potatos, Lime Sulphur versus Bordeaux Mixture as a Spray for. IV, By M. T, 
Munn (U,S.A, Exp, Stn„ Geneva, N.Y., Bull, 421, May 1916).— The author in 
this bulletin again emphasizes the results obtained by use of lime sulphur on 
potatos. 
Lime sulphur as a spray injures the potato foliage, does not prevent the 
blight, and its use results in a marked decrease of tubeis.— C, P, C» 
Potatos in Maine. By C. T. More {U.S.A. Dep. Agr., Circ. 48, April 2, 
1 91 5). — The conditions of potato-growing in Maine#n 191.5 gave rise to dis- 
satisfaction among local growers, as they felt that the prevailing low prices of 
their crops were not justified. The extremely heavy production, together with 
the unsettled conditions, seem to have been responsible for the fall in prices. 
This bulletin suggests improved methods of harvesting and marketing which 
would make for economy and urges rigorous grading of the crop through co- 
operative effort, — M. L. H. 
Prickly Pear and Insects. By W. W, Froggatt (Agr, Gaz. N.S.W., vol. 
xxviii, pp, 417-426; 4 plates). — Attempts to destroy Prickly Pear by Wild 
Cochineal, Round Cactus Scale (Diaspis calyptroides), the Rutherglen Bug 
(Nysius vinilor), and other insects have not been successful. It is now proposed 
to experiment with the large land snail {Helix aspera). — S, E. W. 
Prickly Pear, Destruction of. By G, P, Darnell Smith (Agr. Gaz. N.S.W. 
vol. xxix. pp, 1-12 ; 6 figs.). — At least two operations are necessary completely 
to destroy prickly pear by spraying. The spray is prepared by dissolving 20 lb. 
of white arsenic in 10 gallons of water containing 5 or 10 lb. of caustic soda. 
The application is best made in autumn. This destroys the segments, but in 
order to kill the roots the pears are slashed and re-sprayed. The dead cacti 
are raked together and burnt, — S, E, W a 
Prickly Pears. By J. H. Maiden (Agr, Gaz, N.S.W, vol. xxviii. pp,[65o- 
652 ; 1 coloured plate). — Opuntia vulgaris has ovate joints and numerous short 
prickles, It bears spreading l yellow flowers. This cactus is not found in Australia, 
but the name is frequently incorrectly given to the pest pear O, inermis,- — S. E. W, 
Primula malacoides. By A. W, Hill (Jour, Genetics, vol. vii. pp. 193-198, 
May 1918; plates). — Records the course of development of the now fairly 
numerous varieties of P. malacoides, first introduced to cultivation in 1908. 
F, J. C. 
Prumnopitys elegans. By A, Bruce Jackson (Gard. Chron. Jan. 12, 1918, 
p. 12, with 2 figs.) — 1 ne eighteenth of this series of critical notes on Conifers, Dis- 
cusses establishing a fbparate genus for the group in which the receptacle does 
not become fleshy, under the name Stachycarpus, — E, A , Bd, 
Pyrus triloba. By L, Trabut (Rev, Hort, vol. xc. pp. 8-9; 4 figs,).— 
Pyrus triloba is an ornamental tree valuable on account of its regular growth, 
and its beautiful foliage and flowers, Its fruit resembles that of the crab, It 
is very acid, but is used for making jellies. It is probable that the value of the 
fruit would be improved by cultivation, — S, E, W, 
Radium as a Fertilizer. By C. G, Hopkins and W, H, Sachs (U.S.A, Exp. 
Stn., III., Bull* 177, Jan, 1915). — This bulletin confirms the whole of the experi- 
ments carried out with radium as a fertilizer. The authors clearly demon- 
