Treatment for Pear Blight* 



M. B. Waite, Pathologist, U.S. Department of Agriculture 



' 



AMONG the factors that influence 

 pear blight the presence of the 

 germ is of primary importance. 

 If the pear blight is not present 

 in the orchard or in the immediate 



do, when followed by late treatment. 

 On rapidly growing twigs and branches 

 it is usually necessary to cut a foot or 

 more below the lowest discoloration of 

 the bark. In fall and winter pear blight 



blight is to cut all blight from the trees, 

 and save all the healthy parts that can 

 be saved. Blight completely kills the| 

 bark of that portion of the tree which 

 reaches but leaves the rest of the tre^ 

 wholly uninjured. The 

 only exception to this is 

 where the girdling effect 

 is produced by the blight 

 at the collar or on thei^ 

 branches. Very few or-i; 

 chardists t h o r o u ghlyj 

 know and understand 

 pear blight. It has been 

 with them so long that 

 they regard it as one of 

 the inevitable troubles of 

 the year and, in fact, the 

 apple as well. Still les.s 

 generally known are the 

 modern methods of con- 

 trolling this disease by 

 eradication. 



Scenes Like This are Common in Canada Daring the Spraying Season 



The illustration shows Mr. A. N. Brown of Wyoming, Del., well known in Ontario, and assistants spraying with 



a Niagara Gas Sprayer. 



vicinity there can be no blight. When 

 spring opens up and new growth begins, 

 if the germs are present or conveniently 

 near by, and the conditions favorable, 

 blight has a great opportunity to spread 

 and accomplish its work of destruction. 

 If, on the other hand, the germs do not 

 occur, no matter how favorable condi- 

 tions may be, there can be no blight. 



The main method of controlling pear 

 blight is to cut out the holdover blight. 

 This is usually best done in late summer 

 and autumn but it may be done at any 

 time through the winter or early spring 

 before the blossoms appear. When 

 blight occurs on the main limbs or on the 

 collars of the trees, one of the principal 

 things in combatting the disease is to 

 find all the cases, especially where the 

 blight occurs under the rough bark. It 

 requires close examination to find and 

 remove all the blight in the tops of the 

 trees but this can best be done in the 

 summer or early in the autumn while the 

 foliage is still on, the blackened dead 

 leaves enabling one to easily locate the 

 blighted branches. Summer cutting out 

 of pear blight must be regarded, how- 

 ever, as of secondary importance in the 

 treatment, though still a good thing to 



•This is a continuation of Mr. Waite'« address before 

 Ontarla Fruit Growers' Assoolation. His remarks on 

 Peach Yellows will appear in next issue. 



cutting, it is usually possible to cut pret- 

 ty close to the blight, say four to six 

 inches, or, where it has thoroughly died 

 out, an inch may do. On the other 

 hand, when the blight blends off imper- 

 ceptibly from the dead bark into the live 

 bark, as it often does in summer, from 

 one to two feet below the lowest point 

 may be considered necessary. 



In all work of cutting out pear blight a 

 disinfectant should be carried to sterilize 

 the tools and cut surfaces. For this pur- 

 pose, one of the most convenient germi- 

 cides is a i-iooo solution of corrosive 

 sublimate. A bottle of this can be car- 

 ried in the pocket and a sponge, tied to a 

 string, kept saturated with this solution. 

 After trimming out the blight or remov- 

 ing the blighted bark from a diseased 

 area, the cut surface as well as the in- 

 struments should be sterilized before 

 turning to another infection. It is possi- 

 ble with proper tools such as a gouge, 

 draw shave or box scraper, or, better, a 

 specially made scraper, to remove the 

 bark from a blighted area, disinfect the 

 surface and thus save a large limb or the 

 trunk of a tree instead of removing the 

 same. All small limbs which can be 

 easily spared shpuld be cut out in remov- 

 ing the blight. 



The object of the treatment of pear 

 as 



Spraying Straw- 

 berries 



L. A. Hamilton, Lome Park, Ont] 



The plants on the two- 

 acre plot of strawberries 

 set out on my farm in 



1907 looked so promis- 

 ing in the spring of 



1908 that I determined 

 to give them every 



possible chance to fight down insect and 

 fungous pests. Adopting the formula 

 given by the Norfolk Fruit Growers' 

 Association as a basis, I sprayed heavily 

 on the 2 1 St of May with the following 

 solution : Five pounds of blue vitriol, 

 twelve pounds of lime, four ounces of 

 Paris green to fifty gallons of water. 

 Owing to the high percentage of lime the 

 patch after spraying looked as if it had 

 had a good dusting of snow. 



It would be unwise to lay too much 

 stress on a single experiment of this 

 kind ; but I can only say that we never 

 had such a splendid patch of berries be^ 

 fore on this farm. The plants continued 

 to be strong and vigorous, and absolutely 

 free from injurious insects, rusty and 

 spotted leaves. The leaves held their 

 dark green lustre until the crop was 

 ripened. We gathered 13,000 boxes off 

 the two acres. A finer lot of strawberries 

 I have not seen before in this locality, 

 much superior in size and quality to any 

 thing we had grown before. 



This does not prove that these results 

 were due to spraying. Several other fac 

 tors might have exerted a potent in 

 fluence, such as the plant stock, condi- 

 tion of soil, location, wintering and fruit 

 ing season. But the sprayed plants gavi 

 so much better results than the unspray 



