840 EXPERIMENT STATION KECOED. 



ture of 20° F. lasting ODly a short time did little or no injury to the opening 

 bud, newly opened blossom, or newly set fruit of peach, native plum, pear, 

 and apple, while one-half a degree below this (25^°), although lasting only a 

 few minutes, killed a large percentage of the opening buds, newiy set blossoms, 

 and young fruit of the peaches in a number of cases. In some cases, however, 

 a temperature of 2-1° lasting only a short time left about 25 per cent of the 

 blossoms and 9 per cent of the new^ly set fruits uninjured. The longer the 

 time the killing temperature remains and the nearer it is to sunrise the 

 greater the amount of damage that should be expected. In cases where the 

 minimum temperature occurred at midnight or a little later and then gradually 

 rose to the freezing point so that the frozen buds, blossoms, and fruits had time 

 to thaw out slowly before sunrise the injury was insignificant. Apples and 

 pears seemed to be more resistant than peaches and plums. European and 

 native plums seemed to be slightly hardier than Japanese plums and apricots. 

 Apricots were the least resistant of all the fruits included in the test. 



The susceptibility of most varieties of apricots, plums, and peaches to frost 

 injury emphasizes the importance of choosing late blooming varieties, provided 

 they are at least fairly satisfactory in other respects. The comparative tem- 

 peratures for March and April taken in the valley and on the mesa show that 

 the minimum temperatures were considerably warmer at the latter location. 



Experiments in the dusting" and spraying of apples, F. M. Blodgett {isiew 

 York Cornell Sta. BuL 340 {WW, pp. 149-179, pi. 1, figs. ^).— In the experi- 

 ments here reported finely ground sulphur plus lead arsenate applied both in 

 liquid and dry form were compared with lime-sulphur-lead arsenate solution 

 in the control of apple scab and insect pests. 



The first experiments were started in 1911 but neither scab nor insects were 

 present in sufficient quantity to secure any definite results. It was found, 

 however, that the sulphur mixtures adhered remarkably well to the foliage 

 and fruit and there was no indication of foliage injury or dwarfing. In 1912 

 a mild attack of scab was controlled about equally well by the three different 

 treatments used. Arsenate of lead was about equally effective when applied 

 with the lime-sulphur solution and with a suspension of sulphur. It was con- 

 siderably more effective in the dry mixture than in either of the liquid mix- 

 tures. The experiments were continued on a larger scale in 1913. The details 

 are given as to quantities of material used, dates of application and conditions 

 influencing the same, time required, comparative costs, results, and methods of 

 recording data. 



From the data thus far secured in the investigation the author concludes that 

 the use of finely ground sulphur as a fungicide and a dust mixture has given 

 sufiiciently encouraging results to warrant further trials on a more extensive 

 scale. The application of arsenate of lead in powdered form in the quantities 

 applied is more effective against the common orchard insects that chew than 

 is the same substance applied wet. The cost of material and application of 

 the dust mixture used in 1913 was as great or greater than the application of 

 a wet spray. The time required for dusting an orchard is much less than that 

 required for spraying. The opinion is advanced that the orchardist with addi- 

 tional acreage coming into bearing will probably be warranted in awaiting the 

 results of another year's experimentation before buying additional spraying 

 equipment. 



Plum culture and district lists of plums suitable for Canada with descrip- 

 tions of varieties, W. T. Macoun (Canada Expt. Farms Bui. 43, rev. ed. {1913), 

 pp. 72, figs. 10).— The present edition of this bulletin (E. S. R., 15, p. 476) has 

 been revised to include the information gained from recent experience in con- 

 nection with plum growing at the Central Experimental Farm. 



