FIGHTING THE PINE BLISTER DISEASE 



MAXV inquiries come to American Forestry asking 

 if it is possible to eradicate the pine blister dis- 

 ease or prevent it spreading by spraying. No 

 spray has been found which can be used effectively 

 against the blister rust cither on jMi-es. currant or goose- 

 berry bushes. Spraying is not re:ommended, because 

 the disease spreads very rapidly on currants and to con- 

 siderable distances. A oumber of tests have been made 

 by men who realize the necessity for careful work and 

 who presumably did the most thorough work possible 

 under the circumstances. In Europe, Ewert attempted 

 to spray black currant bushes thoroughly enough to keep 

 the disease off them. He concluded that it was impossi- 

 ble to do it. .\ similar attempt was made by McCubbin 

 in (J.Uario two years ago. He sprayed every two weeks 

 and also concluded that it was an impossibility to keep 

 the disease entirely off the sprayed bushes. Other at- 

 tempts have been made in dift'erent localities with the 

 same results. Unless absolute freedom can be secure! 

 from this disease, spraying is inefficient, since a single 

 rust pustule is sufficient to start the disease upon neigh- 

 boring currants. The disease is known to jump from 

 currant to currant at least one-half mile, and under favor- 

 able conditions it jumps several miles. 



The (|uestion of securing a resistant variety of cur- 

 rant or gooseberry is still in need of further investigation. 

 It is desired that scouts send in to Dr. Perley S.)au!d- 

 ing, United .States Dejiarlment of Agriculture, at Wash- 

 ington, cuttings of currants and gooseberries which 

 show marked resistance to the disease. Only cattings of 

 apparently resistant uninfected jilants which arc uader 

 very severe test conditions, that is, with heavily infected 

 bushes within a few feet, need be sent in. Wrap si)eci- 

 mens in damp (not wet) moss or dead leaves and label 

 with your own name, place where collected and date. 

 State briefly why the specimen is thought to be resistant. 



Experiments are being carried on to obtain if possible 

 some cheap chemical which will kill wild currant and 

 gooseberry bushes. Over 500 experiments are in prog 

 ress, using dift'erent chemicals and methods. \'arious 

 derivatives of arsenic, sulphur and ammonia are be-in;.; 

 used as a spray to kill the foliage. Fuel oil is also being 

 tried. Plots were sprayed with fuel oil and two days 

 later burned over without good results. The soil about 

 the plants in one series of experimental plots is being 

 treated with dry chemicals such as salt, calcium chloride 

 and sodium carbonate. Sodium arsenite, sodium cyanide 

 and fuel oil are injected into the soil near the roots of 

 bushes in liriuid form. Some of the gaseous chemicals 

 employed are sodium sul])hid, sodium l)isulphid. chloride 

 of lime, calcium carl)i<lc. carlxin hisulphid, formalin, 

 chlorine water, hydrogen sulphid water, turpentine, 

 nitro-benzine derivatives, crude carbolic acid, etc. These 



substances are placed in the soil arejund the roots of wild 

 currar.t and gooseberry Ijushes in various tpiantities. 



I'hus far the use of chemicals as outlined above has 

 met with very little success. In addition, mechanical 

 methods of removal are being tested to determine com- 

 parative costs and efficiency in jireventing si)routing from 

 the roots. 



Where men are otherwise liable U) the draft, no ex- 

 emptions, either permanent or temporary, have been 

 granted to Government blister rust workers. However, 

 it is possible that temporary delay in reporting for duty 

 until after the close of the present season's work may 

 be secured for men whose services are highly necessary 

 for the conduct of the work. No request for delay in draft 

 can be made until the men are notified to rejiort for duty 

 at the army camps. It was annoimced that 30 per cent of 

 the (|U0ta of each district would be called on .September n, 

 the ne.xt 30 per cent Septemlier lo and another 30 per 

 cent on .Se|>tember 30. The remaining 10 per cent was to 

 be mobilized as soon after that date as possible. 



The following are the conclusions reached by experts 

 whii have made a study of the ])ine blister disease: 



The essential thing in controlling the blister rust is 

 to get out all currant and gooseberry bushes. The most 

 effective time for doing this is in the early si>ring, and 

 this part of the season should lie used for rescouting con- 

 trol areas. 



It is not feasible to spend time and money in scout- 

 ing and eradicating diseased pine in New England, ex- 

 cept where there nia\' be outbreaks of the disease in new 

 territory. 



The establisliment of control areas, in wliich all cur- 

 rant and gooseberry bushes, both wild and cultivated, 

 shall be eradicated as far as possible, is regarded as the 

 most practicable means of limiting the ravages of white 

 pine blister rust ; and owners of pine woods are urged to 

 co-operate with state authorities to control the disease 

 in their several localities. 



in the expenditiu\- of funds appropriated for blister 

 rust work, the following plans are generally ajjproved. 

 1. The method of direct state experimental areas to de- 

 termine the cost of control by means of the eradication 

 of wild and domestic bushes under various conditions ; 

 and, 2, such co-operation with private owners as will giv 

 expert direction or supervision Id tlu'ir work. 



Localities established as control areas should be 

 scouted at least four successive years for currants and 

 gooseberry bushes. 



Men inspecting should be re(|iiire(l to carry whisl: 

 brooms and to Ijrusii their entire clothing with these 

 after dipjiing them into disinfectant when circumstances 

 require, also thoroughly to wash their hands and arms. 



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