848 EXPERIMENTAL I'AUUS 



5 GEORGE v.. A. 1915 



expense of spraying, yet in certain cases trees are almost completely defoliated by it. 

 When infection occurs at the time when the leaf is expanding the afiected portion 

 dries up and falls out, producing tlie true ' shot hole,' but infection later on in the 

 season may only result in the formation of leaf spots. Control should include the 

 dormant spray of lime-sulphur in the spring and the destruction of affected leaves. 

 Where further measures are needed, half-strength Bordeaux made alkaline by excess 

 of lime may be used, but there is danger of burning the leaves, especially in hot dry 

 weather, if the ordinary mixture is applied. 



PEACH. 



Leaf Cuhl (xcavasus deformans Fuckel). — A few bad cases of Leaf Curl were 

 noted in 1918, and in every case where the disease was met with, the controlling spray 

 of lime-sulphur had either been carelessly apiilied or had not been applied soon enough 

 in the spring. 



CanJcer. — The Gummosis cankers of the peach are quite prevalent thrQughout the 

 peninsula, and while no, notable increase in their number took place during the yeasj 

 those already formed made their usual yearly increase in size. On account of the 

 prevalence of cankers at the bases of twigs killed by Brown Rot and other fungi, it ia 

 advised that care be taken to carefully remove these every summer so that conditions 

 may not be left which are favourable to canker formation the following spring. Treat- 

 ment of cankers which infest the main trunks or limbs of tr'ees is well worth while. 

 These should be carefully cleaned out, washed with corrosive sublimate (1 — 100) and 

 when dry i^ainted with ordinary lead paint. 



Mildew {Spluviotheca pannosa Lev.). — The ordinary commercial varieties are 

 very little troubled with this disease, but a few varieties are very susceptible to it. 

 The Toronto and Breeken are badly attacked and often serve as sources of infection 

 to other nearby trees which would of themselves be immune. The disease is readily 

 controlled by dusting with flowers of sulphur or by the use of self-boiled lime-sulphur 

 applied when the first signs of the disease appear. It is found that none of the suscep- 

 tible varieties possess sufficient advantages over the immune varieties to warrant their 

 retention under conditions that necessitated yearly spraying, so that they are being 

 quickly discarded by all practical growers. 



Yellows and Little PEAfiii:s. — Under the efficient system of inspection now 

 employed by the Provincial Government, these diseases have during the last three 

 years undergone a remarkable and encouraging decrease, and it is hoped that in ensu- 

 ing years the percentage of trees destroyed from this cause will become very small. 



PLUM. 



Rrowx Rot {Sderotinla fruciigena Schr.). — Still continues to take its toll of 

 t]ie plum crop, and was sufficiently serious during 1913 to warrant attention. An 

 attempt to deal with this disease requires: (1) the destruction of rotten fruit by 

 ploughing deeply under, in fall or early spring; (2) the removal and destruction of 

 the mummies from the trees; (") a cleansing spray of lime-sulphur (1.303 sp. gr.) 

 before growth starts, to kill all 'spores adhering to the bark and limbs; (4) summer 

 spray to prevent infection from spores which have escaped (1), (2) and 

 (3), or others which may be brought in from elsewhere. For this spray self -boiled 

 lime-suli^hur is recommended. According to 8cott, the iirst spraying should be given 

 about three weeks after the petals fall, the third a month before the fruit ripens, and. 

 the second midway between the first and third. 



Shot Hole (Cylindrosporium padi, Karst.). — With the exception of Japanese 

 varieties, plums are not usually seriously affected by shot hole. In the Japanese var- 



Ottawa. 



