No. 6. DEPARTMENT OF AGRICULTURE. 591 



days in the time the different varieties can be treated. In the 

 second application it is advisable to add the arsenate of lead or Paris 

 Green to the Bordeaux mixture and destroy the codling moth as well 

 as the apple scab fungus. 



Jhe third treatment should be made seven to ten days later. If 

 the season is dry, from this on additional treatments may not be 

 necessary. However, if the season is moist, two or three additional 

 sprayings at intervals of two weeks may prevent later infections 

 and be of value in saving the crop. The later treatments for apple 

 scab are made when the tree is in full foliage and will be effective 

 in preventing the leaf blight of apples. There are two or three 

 leaf blights caused by different fungi, but they are easily preventable 

 by spraying after the trees are in full leaf. 



BITTER ROT OF APPLE. 



Until the past season this fugus disease has been one of the 

 troublesome problems in orchard pathology. No one had been able 

 to control the disease with even reasonable satisfaction. The dis- 

 ease is particularly abundant through Maryland, Virginia and west 

 to Missouri, through the southern portion of the commercial apple 

 districts of this country. So far as known it rarely destroys fruit in 

 quantity in this State but as it does occur and may some time be in- 

 jurious, you will be interested in the recent successful results. 



It has been extremely destructive in the Yellow Newtown apple 

 districts of Albermarle and adjacent counties of Virginia. In 

 recent years it has been destroying almost the entire crop of many 

 sections. During the past season Mr. W. M. Scott, Orchard Patholo- 

 gist in the Bureau of Plant Industry, carried on a successful series 

 of spraying experiments which showed exactly how to treat the 

 disease and which saved in some cases as high as 98 per cent, of the 

 crop, although on the control trees left unsprayed less than half a 

 dozen sound apples could be found, the entire crop was ruined with 

 this fungus rot. As the result of this extensive series of experi- 

 ments, Mr. Scott outlines the treatment for Bitter Rot as follows: 



Spray with 5-5-50 Bordeaux mixture, beginning June 10th to 15th, 

 five to seven times at intervals of two weeks. 



The results of his experiments showed that much of the spraying 

 previously had been attempted too early in the season, that in order 

 to secure good results it is necessary to begin about the middle of 

 June and keep the fruit thoroughly coated with the Bordeaux mix- 

 ture throughout the summer. After the fruit becomes thorough Iv 

 coated by three or four sprayings, the mixture stays on pretty well 

 until picking time. 



APPLE CANKER. 



We have had a good deal of complaint from Pennsylvania as well 

 as other sections of the country about fungus diseases on the bark 

 of apple trees. There are some half dozen different species of fun^i 

 which produce apple canker. Sometimes these apple canker spots 

 resemble pear blight, and conversely the pear blight disease itself 

 produces dead patches on the limbs and trunks of apple trees re- 

 sembling canker work. Apple canker, as suggested above, is largely 

 checked by dormant spraying with lime sulphur-salt. It is also con- 

 trolled, at least partially, by the Bordeaux mixture spraying. How- 



