August, 1908.] 



139 



Plant Sanitation, 



July being only 0-81 inch and lor August 

 3-76 inches. Although the mixture seems 

 to be quite adhesive, heavy beating rains 

 might take it off the fruit and foliage, 

 so that a large part of its fungicidal 

 value would be lost. 



Peach Brown-Rot and Scab. 

 The self-boiled lime-sulphur mixture 

 heretofore described did not injure the 

 peach foliage or fruit, and proved to be 

 a strong fungicide in its effect on both 

 brown-rot and peach scab, as well as on 

 some leaf diseases. Unboiled sulphur 

 with milk of lime and pure sulphur 

 suspended in water were also used with 

 promising results. 



Sulphur, wherever used in this experi- 

 ment, whether self-boiled or unboiled, 

 applied once or of tener, had more or less 

 effect on the brown-rot disease. Where 

 the self-boiled wash of both full strength 

 and half strength was used, nearly 90 

 per cent, of the crop came through free 

 from the disease. Owing, perhaps, to 

 the late spring frosts, some of the peach 

 pits cracked, and there was considerable 

 proliferation around them which result- 

 ed in a cracking of the skin, thus expos- 

 ing the fruit even on sprayed trees to 

 brown-rot infection. 



It is not at all surprising that this 

 sulphur mixture should be a good fungi- 

 cide ; the gratifying surprise is that it 

 does not injure peach foliage. Under 

 different weather conditions or when 

 boiled with a more active grade of lime 

 it might prove injurious, and for this 

 reason caution should be exercised until 

 further knowledge of its action is 

 obtained. 



Although occasional rains occurred at 

 Koshkonlong, Mo., while the experiment 

 was in progress, the season would be 

 considered rather dry. The rainfall 

 there as recorded by the voluntary 

 observer, Mr. John W. Hitt, was as 

 follows :— For the month of May, 10 89 

 inches; June, 4'9 inches ; and July, U67 

 inches. Enough rain fell to produce 

 considerable injury to peach foliage 

 following applications of Bordeaux 

 mixture and to cause a severe outbreak 

 of brown-rot. During a very wet season, 

 however, the treatment might not be so 

 successful ; in fact, this disease is in- 

 fluenced by so many factors that it 

 seems doubtful whether an entirely 

 satisfactory treatment for it will ever be 

 found. The plum curculio punctures 

 the skin of a, certain percentage of the 

 fruit and thus admits the fungus in 

 spite of all spraying that can be done ; 

 also, some of the leaf-footed plant bugs 

 feed on the rotting and the sound fruit 

 indiscriminately, thus undoubtedly dis- 



tributing the fungus, and perhaps even 

 with their beaks inserting the spores 

 beneath the skin of the fruit. It seems 

 quite impossible to protect against such 

 infections. 



In the case of peach scab the results 

 were very decided. In every plot where 

 sulphur was used before infection took 

 place, this disease was almost completely 

 controlled. Even sulphur suspended in 

 water without the addition of lime seems 

 to be sufficient to control this disease. 

 As a rule, the scab infections on the 

 sprayed fruit were manifested in small 

 specks instead of the large spots and 

 cracks that were so common on the 

 unsprayed fruit. 



A Combined Fungicide and 

 Insecticide. 

 Self-boiled lime-sulphur washes used in 

 the dormant spraying of fruit trees are 

 known to have some effect against the 

 San Jose scale, and, in order to avoid the 

 expense of cooking-plant, a few growers 

 have employed this method of spraying 

 the wash. Entomologists have wisely dis- 

 couraged the use of self-boiled washes 

 because of their inferiority to the boiled 

 preparations, but when used as a fungi- 

 cide in the growing season a self -boiled 

 lime-sulphur wash might be expected to 

 aid considerably in the control of the 

 San Jose scale and other scale insects by 

 the destruction of the crawling lice, and 

 would thus perhaps prevent the infesta- 

 tion of the fruit, a condition especially 

 likely to occur with apples and pears. 

 This would give it a decided advantage 

 over Bordeaux mixture and make it 

 especially useful as a combined fungicide 

 and insecticide in the treatment of large 

 apple trees on which the scale is so diffi- 

 cult to control. Summer applications 

 for the prevention of fungus diseases 

 would thus supplement the dormant 

 treatment of the San Jose scale without 

 extra cost. 



Sulphur is also a well-known remedy 

 for various mites, and the self-boiled 

 wash would probably be of considerable 

 value in the control of the red spider. 



Range of Possible Usefulness. 



The fungicide described in these pages 

 is only in the experimental stage, and it 

 is impossible to predict the extent of its 

 usefulness ; but if it will control apple 

 bitter-rot, as the results so far obtained 

 indicate, it would naturally be expected 

 to prevent apple scab. Although no 

 positive results were obtained with this 

 disease, the indications were that it 

 might easily be controlled with the lime- 

 sulphur wash and the fruit russeting 

 and foliage injury clue to thelu&e of 



