12 LIME-SULPHUR PREPARATIONS FOR APPLE DISEASES. 



EXPERIMENTS IN ARKANSAS. 



At Siloam Springs, Ark., during 1909, Messrs. F. W. Faurot and 

 E. L. Jenne, of the Bureau of Entomology, conducted another set of 

 experiments under the writer's (Hrections. The results of those 

 experiments throw considerable doubt on both the efficiency and 

 safety of the commercial lime-sulphur solution as a summer spray for 

 apple diseases. The Ben Davis, Shannon, Arkansas, and Elkhorn 

 varieties were sprayed with several different strengths of the commer- 

 cial preparation in combination with arsenical poisons. The self- 

 boiled lime-sulphur solution and the Bordeaux mixture were also 

 used. The trees were sprayed five times, as follows: (1) As soon as 

 the petals fell; (2) three weeks later; (3) eight to nine weeks after 

 the petals fell; (4) two weeks later, and (5) three weeks after the 

 fourth application. 



RESULTS OF THE TREATMENT. 



The trees sprayed with commercial lime-sulphur solution diluted 

 to contain 1 gallon in 30 gallons of water, with the addition of the 

 usual amount of arsenate of lead, showed very little or practically no 

 foliage injury after the first and second applications; in fact, according 

 to notes made on June 30 and July 22, no serious injury followed the 

 third treatment, which was applied on June 2. After the fifth appli- 

 (;ation, however, the injury increased rapidly, and at picking time 

 half of the leaves were on the ground. It seems that the injurious 

 effect of the mixture was cumulative, the injury being increased 

 by each application. Three applications would, perhaps, have 

 resulted in little or no damage, but five sprayings were evidently 

 more than the trees could stand. Considerable rain fell during May 

 and June, but the remainder of the season was dry. The trees suf- 

 fered severely from drought, which apparently exaggerated the spray 

 injury. On account of the shortage of foliage on the trees a portion 

 of the fruit was sunburned, but no russeting was caused by the spray. 

 This sunburning also occurred on the fruit sprayed with Bordeaux 

 mixture, but to a much less extent. 



The commercial lime-sulphur at a strength of 1 to 30 in combina- 

 tion with Paris green began to burn the foliage soon after the first 

 application was made, and by midsummer the trees were almost bare. 

 Arsenite of lime was also used with the 1 to 30 solution, and the 

 results were disastrous. The foliage was burned to a crisp and the 

 fruit badly scorched by the first application. Even the new twig 

 growth was killed to a considerable extent. 



The self-boiled lime-sulphur and arsenate of lead caused no injury 

 to fruit or foliage. The fruit sprayed with Bordeaux mixture was 

 quite badly russeted and the foliage suffered considerable injury. 



[Civ. 54] 



