NOTES AND ABSTRACTS. 
Pollination, Plum. By A. H. Hendrickson {U.S.A. Exp. Shi. Calif., 
Bull. 310, figs.). — Seventeen varieties of Plums and Prunes were tested as to 
whether they are able to set fruit when self-pollinated or not, of which thirteen 
were found to be self-sterile, three self-fertile, and one " doubtful." 
Of the five European varieties included — Clyman, Tragedy, Grand Duke, 
Yellow Egg, and Ponds — the four first-named were found to be self-sterile, 
whilst Ponds is the " doubtful " one. All five produced pollen abundantly, 
and were found to cross-pollinate one another successfully. 
No intersterility among plums or prunes was found. Both for cross-pollina- 
tion, and as an agency for distributing pollen among the self-fertile varieties, 
bees were found to increase the percentage of fruit-setting. — A. N. R. 
Pollination, Prune-, The Common Honey Bee as an Agent in. By A. H. Hendrick- 
son {U.S.A. Exp. Stn. Calif., Bulls. 274 and 291). — Over a series of experiments 
the author finds that both the French and Imperial Prunes may be aided in 
setting fruit by the use of bees in the orchard at blossoming time. Tables are given 
showing that the absence of bees in the orchard may mean a low percentage of 
fruit-setting with both of the varieties. — A . N. R. 
Pollination of Bartlett Pear. By W. P. Tufts {U.S.A. Exp. Stn. Calif., 
Bull. 307 ; figs.). — This report gives a full account of the experiments conducted 
to show to what extent the Bartlett Pear is self-fertile or sterile in different 
localities, and to discover the best varieties to interplant for cross-pollina- 
tion. It is found that this variety is self-sterile under foothill conditions, 
and also to a limited degree under valley conditions. All varieties tested gave 
satisfactory artificial germination of pollen, and it is shown that there is little 
variation in the amount of pollen produced by each one. No cases of inter- 
sterility among pears was found. The importance of interplanting is emphasized 
and varieties are quoted as being suitable for this purpose. One hive of bees to 
each acre of orchard is advised. — A . N. R. 
Poppy, Flower colour and associated characters of the Opium. By H. M. 
Leake and B. Bam Pershad (Jour. Gen. x. pp. 1-20 ; July 1920). — A summary 
of observations and experimental breeding-results with the opium poppy, giving 
an annotated list of the factors which go to the making of flower and seed colour 
in that plant. — F. J. C. 
Potato Diseases in Hawaii. By C. W. Carpenter (U.S. Exp. Stn. Hawaii, 
Bi ll. 45, Jan. 1920, pp. 1-42 ; 1 5 plates). — The growing of Irish potatos in Hawaii, 
though an industry of great importance, has been largely discouraged in recent 
years by persistent crop failures and unfavourable marketing conditions. It 
is hoped that the island may become self-supporting in this commodity, and 
it is believed the potato crop could be doubled by the adoption of modem 
methods of cultivation. The various causes of crop failure have been largely 
due to poor seed, continuous cropping, unsuitable soils, and diseases and insect 
pests. The diseases found in Hawaii include the fusarium wilt, the late blight 
{Phytophthora infestans), Rhizodonia Solani, Sclerotium Rolfsii, common corky 
scab {Actinomyces ckromogenus) , and the non-parasitic troubles — sun-scald, leaf- 
tip burn, hollow potato tuber, 'and sunburn of tubers. 
■ The universal adoption of^seed selection and disinfection, crop rotation ar.d 
spraying with Bordeaux mixture are recommended as means for a general 
improvement in the potato cultivation. — A . B. 
Potato Eelworm. By A. L. Lovett {Board Hort. Rep. Oregon, 1919, pp. loi- 
104: 3 figs.). — It is useless to plant potatos in ground infested with eelworms. 
For three years grow crops practically not liable to attack, such as barley, maize, 
peanut, pearl millet, rye, wheat, Timothy or winter oats. — 5. E. W. 
Potato Leaf-Burn. By E. D. Hall {Iowa State Hort. Soc. Trans. 191 8. pp. 335- 
336). — Much damage to the potato crop is done by leaf bum, due to the 
attack of a small green hopper {Empoasca mali). Spraying the under surface 
of the leaves with kerosine emulsion is the best remedy. — 5. E. W. 
Potato, Streak Disease of. By W. A. Orton {Phytopaihology. x. p. 97, Feb. 
1920 ; figs.). — The streaky appearance appears first in the upper leaves of normally 
developed plants and spreads downwards by the veinlets to the stem, which 
eventually collapses. The author suspects the disease to be of bacterial origin, 
but no organism has yet been found. — F. J. C. 
