February, 1922 BETTER FRUIT P''^' ^^^^« 



Control of Anthracnose, or Black Spot Canker 



Bij E. W. White 



District Horticulturist, Department of Agriculture, Victoria, B. C. 



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I // is a pleasure to present such an 



I arwy oj substantial, concrete data as 



I are given by Professor White in this 



I paper, on the control of one of the 



I most troublesome afple-tree diseases 



I our readers encounter. It is the sub- 



I stance of an address given last stiTn- 



I mer at a conference of horticulturists 



I at Hood River, and delayed in sub- 



I mission to us. No little value is 



I added through inclusion of detailed 



I figures cm spraying costs. As a 



I u-hole, the article is so meaty the 



I hand that might have cut it to con- 



1 siderahly shorter length was stayed, 



I and the report is given in full. 



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APPLE-TREE anthracnose, or black 

 spot cancer, is prevalent in practi- 

 cally all apple orchards of the coast 

 districts of Oregon, Washington and British 

 Columbia, where control measures are not 

 regularly adopted. It is perhaps the most 

 serious fungus disease with which the coast 

 fruit grower has to deal and, during the 

 past twenty-five or thirty years, has caused 

 the destruction of a great number of apple 

 trees with corresponding financial loss. 



It is not the intention in this paper to 

 discuss the origin or life history of this 

 disease or the proper scientific name by 

 which it should be known, but rather to 

 give briefly the results of five years' ex- 

 ■ perimental work in the control of this 

 trouble, carried out in the Keating district 

 near Victoria, Vancouver Island, B. C. 



In past years the general recommendation 

 given to our growers for the control of this 

 disease was to spray with double strength 

 Bordeaux (8-8-40) as soon as the fruit was 

 picked and before the fall rains commenced. 

 Where this system of spraying was followed 

 out very efficient results were obtained, 

 especially on early varieties of apples. Even 

 on late varieties, in a good many cases, the 

 disease was held in check where the spray- 

 ing was done thoroughly. 



The trouble with this control measure, 

 however, was not due to the inefficiency of 

 the spr.iy, but to the fact that the harvest- 

 ing period is always a busy time for fruit 

 growers and in the majority of cases early 

 varieties were not sprayed when the fruit 

 was harvested, and by the time the late 

 apples were picked the wet weather had 

 set in and it was often very difficult to get 

 a fine day on which to do the spraying. In 

 consequence infection took place and each 

 year more dead wood could be found in the 

 orchards. 



Our growers were becoming discouraged 



in their efforts to control the disease and 

 were claiming that it could not be done 

 economically and efficiently. 



Consequently in the fall of 1916 the 

 Horticultural Branch, in co-operation with 

 J. W. Eastham, provincial plant pathologist, 

 decided to do some experimental or perhaps 

 better, some demonstration spraying. 



In outlining the work we were very 

 grateful for information relative to the 

 success achieved in controlling the disease 

 by Leroy Childs, director of the Hood 

 River Experiment Station, by combining a 

 Bordeaux spray with the last codling moth 

 spray. 



It was confidently felt that the disease 

 could be controlled on early apples and for 

 that reason a late variety was chosen with 

 which to work. A block of 36 twenty-year- 

 old Baldwin trees was selected in the or- 

 chard of Tanner Bros. Keating. These trees 

 were very badly diseased and the owners had 

 threatened to cut them out on numerous 

 occasions. In fact, the disease was so bad 

 that practically every bit of new wood 

 which grew each year would be girdled by 

 the canker the following spring. Nothing 

 but the bare framework of the tree and in- 

 numerable dead shoots were left to consti- 

 tute the tree. In 1916 the trees were carry- 

 ing a very light crop of fruit, it being the 

 off-year for bearing. 



In planning to apply a weak Bordeaux 

 early, while the fruit was still on the tree, 

 it was thought that it would be necessary 

 to wipe the fruit before marketing, but this 

 w.is found to be unnecessary. 



THE block of trees was laid out in four 

 plots, the first nine trees in each row 

 constituting Plots 1, 2, and 3, and the last 

 three trees in each row constituting Plot 

 4, or check-plot. Plot 1 received only an 

 early spray of weak Bordeaux, 3-4-40. 

 Plot 2 received an- early and late spray of 

 lyeak Bordeaux, 3-4-40 and strong Bor- 

 deaux, 6-6-40. Plot 3 received only the 

 late spray of strong Bordeaux, 6-6-40. 

 Plot 4 was check-plot and received nothing. 



In 1916 the first spray of 3-4-40 

 Bordeaux was applied on September 6, 

 after a very dry summer, to Plots 1 and 2, 

 constituting 18 trees; 80 gallons of spray 

 mixture was used, averaging 4.44 gallons 

 per tree. 



The cost of materials and application for 

 the first spraying was as follows: 



at .10 $ .60 



not a drop of rain fell up to the time the 

 apples were harvested about October 21. 

 In consequence of this there was a heavy 

 coating of Bordeaux still adhering to the 

 fruit when it was picked. The dry weather 

 also caused a shortage of water and we 

 were unable to carry out our original plan 

 of putting on the second application as soon 

 as the fult was picked. 



Rain began to fall on October 25 and 

 continued intermittently until November 

 8. On this date the weather was favor- 

 able and the second spray of 6-6-40 

 Bordeaux was applied to Plots 2 and 3. 

 Eighty gallons of mixture was made up 

 and there was sufficient to spray 4 trees 

 besides the 18 in Plots 2, and 3, so that 

 the average number of gallons per tree were 

 3.63. 



The cost of material and application for 



the second spraying was as follows: 



12 lbs. Copper Sulphate at .10 $1.20 



12 lbs. Lime at .02 24 



2 nozzle-men, 1 hour at .25 50 



Man and team, 1 hour at $4.00 per day. . . .50 



6 lbs. Copper Sulphate 



8 lbs. Lime at .02 16 



I nozzlcmen, 1 hour at .25 each 50 



Man and team, 1 hour at $4.00 per day. . .50 



Total Cost.... $2.44 

 Cost per tree, second application. . 11.09 cents 



In both sprayings and in the following 

 sprayings a Bean Giant Triplex power 

 sprayer was used and a pressure between 

 180-200 lbs. was maintained. The long- 

 distance Friend nozzle was used in all 

 sprayings. 



Storing and Packing of Sprayed 

 Apples, 1916 — After the apples were 

 picked on October 21 they were placed in 

 orchard boxes in ordinary shed storage and 

 held until the first week in February, 

 1917. Thev ivere then packed and sold 

 (Continued on page 21) 



Total Cost $1.76 



Cost per tree, first application. .. .9.77 cents 

 Following the application on September 

 6, the dry spell continued and practically 



Apple tree in British Columbia orchard, showmg 



damage done by anthracnose, also cankers on trunk 



and branches 



